The following Structured Product Label (SPL) was submitted to the FDA by Aurobindo Pharma Limited for the product Efavirenz (NDC 65862-049). This document serves as the official prescribing information, containing essential scientific data and clinical materials required for healthcare providers and patients.
This specific version of the label includes detailed information regarding 1 indications and usage, 2.1 hepatic function, 2.2 adults, 2.3 pediatric patients, 2.4 capsule sprinkle method of administration, 3 dosage forms and strengths, 4 contraindications, 5.1 drug interactions, and other regulatory disclosures. Use the navigation below to review specific sections of the FDA submission.
Efavirenz tablets in combination with other antiretroviral agents are indicated for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults and in pediatric patients at least 3 months old and weighing at least 3.5 kg.
Monitor hepatic function prior to and during treatment with efavirenz tablets [see Warnings and Precautions (5.9)].
Efavirenz tablets are not recommended in patients with moderate or severe hepatic impairment (Child Pugh B or C) [see Warnings and Precautions (5.9) and Use in Specific Populations (8.6)].
The recommended dosage of efavirenz tablets is 600 mg orally, once daily, in combination with a protease inhibitor and/or nucleoside analogue reverse transcriptase inhibitors (NRTIs). It is recommended that efavirenz tablets be taken on an empty stomach, preferably at bedtime. The increased efavirenz concentrations observed following administration of efavirenz tablets with food may lead to an increase in frequency of adverse reactions [see Clinical Pharmacology (12.3)]. Dosing at bedtime may improve the tolerability of nervous system symptoms [see Warnings and Precautions (5.6), Adverse Reactions (6.1), and Patient Counseling Information (17)]. Efavirenz tablets should be swallowed intact with liquid. For patients who cannot swallow tablets, the capsule sprinkle method of administration is recommended [see Dosage and Administration (2.4)].
Concomitant Antiretroviral Therapy
Efavirenz tablets must be given in combination with other antiretroviral medications [see Indications and Usage (1), Warnings and Precautions (5.3), Drug Interactions (7.1), and Clinical Pharmacology (12.3)].
Dosage Adjustment
If efavirenz is coadministered with voriconazole, the voriconazole maintenance dose should be increased to 400 mg every 12 hours and the efavirenz dose should be decreased to 300 mg once daily using the capsule formulation (one 200 mg and two 50 mg capsules or six 50 mg capsules). Efavirenz tablets must not be broken. [See Drug Interactions (7.1, Table 5) and Clinical Pharmacology (12.3, Tables 7 and 8).]
If efavirenz is coadministered with rifampin to patients weighing 50 kg or more, an increase in the dose of efavirenz to 800 mg once daily is recommended [see Drug Interactions (7.1, Table 5) and Clinical Pharmacology (12.3, Table 8)].
It is recommended that efavirenz tablets be taken on an empty stomach, preferably at bedtime. Table 1 describes the recommended dose of efavirenz tablets for pediatric patients 3 months of age or older and weighing between 3.5 kg and 40 kg [see Clinical Pharmacology (12.3)]. The recommended dosage of efavirenz tablets for pediatric patients weighing 40 kg or greater is 600 mg once daily. For pediatric patients who cannot swallow capsules, the capsule contents can be administered with a small amount of food or infant formula using the capsule sprinkle method of administration [see Dosage and Administration (2.4)].
| Patient Body Weight | Efavirenz Daily Dose | Number of Capsulesa or Tabletsb and Strength to Administer |
|---|---|---|
| a Capsules can be administered intact or as sprinkles [see Dosage and Administration (2.4)]. b Tablets must not be crushed. | ||
| 3.5 kg to less than 5 kg | 100 mg | two 50 mg capsules |
| 5 kg to less than 7.5 kg | 150 mg | three 50 mg capsules |
| 7.5 kg to less than 15 kg | 200 mg | one 200 mg capsule |
| 15 kg to less than 20 kg | 250 mg | one 200 mg + one 50 mg capsule |
| 20 kg to less than 25 kg | 300 mg | one 200 mg + two 50 mg capsules |
| 25 kg to less than 32.5 kg | 350 mg | one 200 mg + three 50 mg capsules |
| 32.5 kg to less than 40 kg | 400 mg | two 200 mg capsules |
| at least 40 kg | 600 mg | one 600 mg tablet OR three 200 mg capsules |
For pediatric patients at least 3 months old and weighing at least 3.5 kg and adults who cannot swallow capsules or tablets, the capsule contents may be administered with a small amount (1 to 2 teaspoons) of food. Use of infant formula for mixing should only be considered for those young infants who cannot reliably consume solid foods. Patients and caregivers should be instructed to open the capsule carefully to avoid spillage or dispersion of the capsule contents into the air. The capsule should be held horizontally over a small container and carefully twisted to open. For patients able to tolerate solid foods, the entire capsule contents should be gently mixed with an age-appropriate soft food, such as applesauce, grape jelly, or yogurt, in the small container. For young infants receiving the capsule sprinkle-infant formula mixture, the entire capsule contents should be gently mixed into 2 teaspoons of reconstituted room temperature infant formula in a small container by carefully stirring with a small spoon, and then drawing up the mixture into a 10 mL oral dosing syringe for administration. After administration of the efavirenz-food or -formula mixture, an additional small amount (approximately 2 teaspoons) of food or formula must be added to the empty mixing container, stirred to disperse any remaining efavirenz residue, and administered to the patient. The efavirenz-food or -formula mixture should be administered within 30 minutes of mixing. No additional food should be consumed for 2 hours after administration of efavirenz.
Efavirenz tablets USP 600 mg are yellow colored oval biconvex film-coated tablets debossed ‘D’ on one side and ‘37’ on other side.
Efavirenz plasma concentrations may be altered by substrates, inhibitors, or inducers of CYP3A. Likewise, efavirenz may alter plasma concentrations of drugs metabolized by CYP3A or CYP2B6. The most prominent effect of efavirenz at steady-state is induction of CYP3A and CYP2B6 [see Dosage and Administration (2.2) and Drug Interactions (7.1)].
QTc prolongation has been observed with the use of efavirenz [see Drug Interactions (7.3, 7.4) and
Clinical Pharmacology (12.2)]. Consider alternatives to efavirenz when coadministered with a drug with a known risk of Torsade de Pointes or when administered to patients at higher risk of Torsade de Pointes.
Efavirenz must not be used as a single agent to treat HIV-1 infection or added on as a sole agent to a failing regimen. Resistant virus emerges rapidly when efavirenz is administered as monotherapy. The choice of new antiretroviral agents to be used in combination with efavirenz should take into consideration the potential for viral cross-resistance.
Coadministration of efavirenz with ATRIPLA (efavirenz 600 mg/emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) is not recommended unless needed for dose adjustment (e.g., with rifampin), since efavirenz is one of its active ingredients.
Serious psychiatric adverse experiences have been reported in patients treated with efavirenz. In controlled trials of 1008 patients treated with regimens containing efavirenz for a mean of 2.1 years and 635 patients treated with control regimens for a mean of 1.5 years, the frequency (regardless of causality) of specific serious psychiatric events among patients who received efavirenz or control regimens, respectively, were severe depression (2.4%, 0.9%), suicidal ideation (0.7%, 0.3%), nonfatal suicide attempts (0.5%, 0), aggressive behavior (0.4%, 0.5%), paranoid reactions (0.4%, 0.3%), and manic reactions (0.2%, 0.3%). When psychiatric symptoms similar to those noted above were combined and evaluated as a group in a multifactorial analysis of data from Study 006, treatment with efavirenz was associated with an increase in the occurrence of these selected psychiatric symptoms. Other factors associated with an increase in the occurrence of these psychiatric symptoms were history of injection drug use, psychiatric history, and receipt of psychiatric medication at study entry; similar associations were observed in both the efavirenz and control treatment groups. In Study 006, onset of new serious psychiatric symptoms occurred throughout the study for both efavirenz-treated and control- treated patients. One percent of efavirenz-treated patients discontinued or interrupted treatment because of one or more of these selected psychiatric symptoms. There have also been occasional postmarketing reports of death by suicide, delusions, and psychosis-like behavior although a causal relationship to the use of efavirenz cannot be determined from these reports. Postmarketing cases of catatonia have also been reported and may be associated with increased efavirenz exposure. Patients with serious psychiatric adverse experiences should seek immediate medical evaluation to assess the possibility that the symptoms may be related to the use of efavirenz, and if so, to determine whether the risks of continued therapy outweigh the benefits. [See Adverse Reactions (6.1)].
Fifty-three percent (531/1008) of patients receiving efavirenz in controlled trials reported central nervous system symptoms (any grade, regardless of causality) compared to 25% (156/635) of patients receiving control regimens [see Adverse Reactions (6.1, Table 3)]. These symptoms included, but were not limited to, dizziness (28.1% of the 1008 patients), insomnia (16.3%), impaired concentration (8.3%), somnolence (7%), abnormal dreams (6.2%), and hallucinations (1.2%). These symptoms were severe in 2% of patients; and 2.1% of patients discontinued therapy as a result. These symptoms usually begin during the first or second day of therapy and generally resolve after the first 2 to 4 weeks of therapy. After 4 weeks of therapy, the prevalence of nervous system symptoms of at least moderate severity ranged from 5% to 9% in patients treated with regimens containing efavirenz and from 3% to 5% in patients treated with a control regimen. Patients should be informed that these common symptoms were likely to improve with continued therapy and were not predictive of subsequent onset of the less frequent psychiatric symptoms [see Warnings and Precautions (5.5)]. Dosing at bedtime may improve the tolerability of these nervous system symptoms [see Dosage and Administration (2)].
Analysis of long-term data from Study 006 (median follow-up 180 weeks, 102 weeks, and 76 weeks for patients treated with efavirenz + zidovudine + lamivudine, efavirenz + indinavir, and indinavir + zidovudine + lamivudine, respectively) showed that, beyond 24 weeks of therapy, the incidences of new-onset nervous system symptoms among efavirenz-treated patients were generally similar to those in the indinavir-containing control arm.
Late-onset neurotoxicity, including ataxia and encephalopathy (impaired consciousness, confusion, psychomotor slowing, psychosis, delirium), may occur months to years after beginning efavirenz therapy. Some events of late-onset neurotoxicity have occurred in patients with CYP2B6 genetic polymorphisms which are associated with increased efavirenz levels despite standard dosing of efavirenz. Patients presenting with signs and symptoms of serious neurologic adverse experiences should be evaluated promptly to assess the possibility that these events may be related to efavirenz use, and whether discontinuation of efavirenz is warranted.
Patients receiving efavirenz should be alerted to the potential for additive central nervous system effects when efavirenz is used concomitantly with alcohol or psychoactive drugs.
Patients who experience central nervous system symptoms such as dizziness, impaired concentration, and/or drowsiness should avoid potentially hazardous tasks such as driving or operating machinery.
Efavirenz may cause fetal harm when administered during the first trimester to a pregnant woman. Advise females of reproductive potential who are receiving efavirenz to avoid pregnancy. [See Use in Specific Populations (8.1 and 8.3)].
In controlled clinical trials, 26% (266/1008) of adult patients treated with 600 mg efavirenz experienced new-onset skin rash compared with 17% (111/635) of those treated in control groups [see Adverse Reactions (6.1)]. Rash associated with blistering, moist desquamation, or ulceration occurred in 0.9% (9/1008) of patients treated with efavirenz. The incidence of Grade 4 rash (e.g., erythema multiforme, Stevens-Johnson syndrome) in adult patients treated with efavirenz in all studies and expanded access was 0.1%. Rashes are usually mild-to-moderate maculopapular skin eruptions that occur within the first 2 weeks of initiating therapy with efavirenz (median time to onset of rash in adults was 11 days) and, in most patients continuing therapy with efavirenz, rash resolves within 1 month (median duration, 16 days). The discontinuation rate for rash in adult clinical trials was 1.7% (17/1008).
Rash was reported in 59 of 182 pediatric patients (32%) treated with efavirenz [see Adverse Reactions (6.2)]. Two pediatric patients experienced Grade 3 rash (confluent rash with fever, generalized rash), and four patients had Grade 4 rash (erythema multiforme). The median time to onset of rash in pediatric patients was 28 days (range 3 to 1642 days). Prophylaxis with appropriate antihistamines before initiating therapy with efavirenz in pediatric patients should be considered.
Efavirenz can generally be reinitiated in patients interrupting therapy because of rash. Efavirenz should be discontinued in patients developing severe rash associated with blistering, desquamation, mucosal involvement, or fever. Appropriate antihistamines and/or corticosteroids may improve the tolerability and hasten the resolution of rash. For patients who have had a life-threatening cutaneous reaction (e.g., Stevens-Johnson syndrome), alternative therapy should be considered [see Contraindications (4)].
Postmarketing cases of hepatitis, including fulminant hepatitis progressing to liver failure requiring transplantation or resulting in death, have been reported in patients treated with efavirenz. Reports have included patients with underlying hepatic disease, including coinfection with hepatitis B or C, and patients without pre-existing hepatic disease or other identifiable risk factors.
Efavirenz is not recommended for patients with moderate or severe hepatic impairment. Careful monitoring is recommended for patients with mild hepatic impairment receiving efavirenz. [see Adverse Reactions (6.1) and Use in Specific Populations (8.6)].
Monitoring of liver enzymes before and during treatment is recommended for all patients [see Dosage and Administration (2.1)]. Consider discontinuing efavirenz in patients with persistent elevations of serum transaminases to greater than five times the upper limit of the normal range.
Discontinue efavirenz if elevation of serum transaminases is accompanied by clinical signs or symptoms of hepatitis or hepatic decompensation.
Convulsions have been observed in adult and pediatric patients receiving efavirenz, generally in the presence of known medical history of seizures [see Nonclinical Toxicology (13.2)]. Caution should be taken in any patient with a history of seizures. Patients who are receiving concomitant anticonvulsant medications primarily metabolized by the liver, such as phenytoin and phenobarbital, may require periodic monitoring of plasma levels [see Drug Interactions (7.1)].
Treatment with efavirenz has resulted in increases in the concentration of total cholesterol and triglycerides [see Adverse Reactions (6.1)]. Cholesterol and triglyceride testing should be performed before initiating efavirenz therapy and at periodic intervals during therapy.
Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including efavirenz. During the initial phase of combination antiretroviral treatment, patients whose immune system responds may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci pneumonia [PCP], or tuberculosis), which may necessitate further evaluation and treatment.
Autoimmune disorders (such as Graves’ disease, polymyositis, Guillain-Barré syndrome, and autoimmune hepatitis) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable, and can occur many months after initiation of treatment.
Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and “cushingoid appearance” have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.
The most significant adverse reactions observed in patients treated with efavirenz are:
Because clinical studies are conducted under widely varying conditions, the adverse reaction rates reported cannot be directly compared to rates in other clinical studies and may not reflect the rates observed in clinical practice.
Adverse Reactions in Adults
The most common (>5% in either efavirenz treatment group) adverse reactions of at least moderate severity among patients in Study 006 treated with efavirenz in combination with zidovudine/lamivudine or indinavir were rash, dizziness, nausea, headache, fatigue, insomnia, and vomiting.
Selected clinical adverse reactions of moderate or severe intensity observed in ≥2% of efavirenz-treated patients in two controlled clinical trials are presented in Table 2.
| Adverse Reactions | Study 006 LAM-, NNRTI-, and Protease Inhibitor-Naive Patients | Study ACTG 364 NRTI-experienced, NNRTI-, and Protease Inhibitor-Naive Patients | ||||
|---|---|---|---|---|---|---|
| Efavirenzb+ ZDV/LAM (n=412) 180 weeksc | Efavirenzb+ Indinavir (n=415) 102 weeksc | Indinavir + ZDV/LAM (n=401) 76 weeksc | Efavirenzb + Nelfinavir + NRTIs (n=64) 71.1 weeksc | Efavirenzb + NRTIs (n=65) 70.9 weeksc | Nelfinavir + NRTIs (n=66) 62.7 weeksc | |
| a Includes adverse events at least possibly related to study drug or of unknown relationship for Study 006. Includes all adverse events regardless of relationship to study drug for Study ACTG 364. b Efavirenz provided as 600 mg once daily. c Median duration of treatment. d Includes erythema multiforme, rash, rash erythematous, rash follicular, rash maculopapular, rash petechial, rash pustular, and urticaria for Study 006 and macules, papules, rash, erythema, redness, inflammation, allergic rash, urticaria, welts, hives, itchy, and pruritus for ACTG 364. — = Not Specified. ZDV = zidovudine, LAM = lamivudine. | ||||||
| Body as a Whole | ||||||
| Fatigue | 8% | 5% | 9% | 0 | 2% | 3% |
| Pain | 1% | 2% | 8% | 13% | 6% | 17% |
| Central and Peripheral Nervous System | ||||||
| Dizziness | 9% | 9% | 2% | 2% | 6% | 6% |
| Headache | 8% | 5% | 3% | 5% | 2% | 3% |
| Insomnia | 7% | 7% | 2% | 0 | 0 | 2% |
| Concentration impaired | 5% | 3% | <1% | 0 | 0 | 0 |
| Abnormal dreams | 3% | 1% | 0 | — | — | — |
| Somnolence | 2% | 2% | <1% | 0 | 0 | 0 |
| Anorexia | 1% | <1% | <1% | 0 | 2% | 2% |
| Gastrointestinal | ||||||
| Nausea | 10% | 6% | 24% | 3% | 2% | 2% |
| Vomiting | 6% | 3% | 14% | — | — | — |
| Diarrhea | 3% | 5% | 6% | 14% | 3% | 9% |
| Dyspepsia | 4% | 4% | 6% | 0 | 0 | 2% |
| Abdominal pain | 2% | 2% | 5% | 3% | 3% | 3% |
| Psychiatric | ||||||
| Anxiety | 2% | 4% | <1% | — | — | — |
| Depression | 5% | 4% | <1% | 3% | 0 | 5% |
| Nervousness | 2% | 2% | 0 | 2% | 0 | 2% |
| Skin & Appendages | ||||||
| Rashd | 11% | 16% | 5% | 9% | 5% | 9% |
| Pruritus | <1% | 1% | 1% | 9% | 5% | 9% |
Pancreatitis has been reported, although a causal relationship with efavirenz has not been established. Asymptomatic increases in serum amylase levels were observed in a significantly higher number of patients treated with efavirenz 600 mg than in control patients (see Laboratory Abnormalities).
Nervous System Symptoms
For 1008 patients treated with regimens containing efavirenz and 635 patients treated with a control regimen in controlled trials, Table 3 lists the frequency of symptoms of different degrees of severity and gives the discontinuation rates for one or more of the following nervous system symptoms: dizziness, insomnia, impaired concentration, somnolence, abnormal dreaming, euphoria, confusion, agitation, amnesia, hallucinations, stupor, abnormal thinking, and depersonalization [see Warnings and Precautions (5.6)]. The frequencies of specific central and peripheral nervous system symptoms are provided in Table 2.
| Percent of Patients with: | Efavirenz 600 mg Once Daily (n=1008) % | Control Groups (n=635) % |
|---|---|---|
| a Includes events reported regardless of causality. b Data from Study 006 and three Phase 2/3 studies. c “Mild” = Symptoms which do not interfere with patient’s daily activities. d “Moderate” = Symptoms which may interfere with daily activities. e “Severe” = Events which interrupt patient’s usual daily activities. | ||
| Symptoms of any severity Mild symptomsc Moderate symptomsd Severe symptomse Treatment discontinuation as a result of symptoms | 52.7 33.3 17.4 2 2.1 | 24.6 15.6 7.7 1.3 1.1 |
Psychiatric Symptoms
Serious psychiatric adverse experiences have been reported in patients treated with efavirenz. In controlled trials, psychiatric symptoms observed at a frequency greater than 2% among patients treated with efavirenz or control regimens, respectively, were depression (19%, 16%), anxiety (13%, 9%), and nervousness (7%, 2%).
Rash
In controlled clinical trials, the frequency of rash (all grades, regardless of causality) was 26% for 1008 adults treated with regimens containing efavirenz and 17% for 635 adults treated with a control regimen. Most reports of rash were mild or moderate in severity. The frequency of Grade 3 rash was 0.8% for efavirenz-treated patients and 0.3% for control groups, and the frequency of Grade 4 rash was 0.1% for efavirenz and 0 for control groups. The discontinuation rates as a result of rash were 1.7% for efavirenz-treated patients and 0.3% for control groups [see Warnings and Precautions (5.8)].
Experience with efavirenz in patients who discontinued other antiretroviral agents of the NNRTI class is limited. Nineteen patients who discontinued nevirapine because of rash have been treated with efavirenz. Nine of these patients developed mild-to-moderate rash while receiving therapy with efavirenz, and two of these patients discontinued because of rash.
Selected Grade 3 to 4 laboratory abnormalities reported in ≥2% of efavirenz-treated patients in two clinical trials are presented in Table 4.
| a Efavirenz provided as 600 mg once daily. b Median duration of treatment. c Isolated elevations of GGT in patients receiving efavirenz may reflect enzyme induction not associated with liver toxicity. d Nonfasting. ZDV = zidovudine, LAM = lamivudine, ULN = upper limit of normal, ALT = alanine aminotransferase, AST = aspartate aminotransferase, GGT = gamma-glutamyltransferase. | |||||||
| | | Study 006 LAM-, NNRTI-, and Protease Inhibitor-Naive Patients | Study ACTG 364 NRTI-experienced, NNRTI-, and Protease Inhibitor-Naive Patients | ||||
| Variable | Limit | Efavirenza + ZDV/LAM (n=412) 180 weeksb | Efavirenza + Indinavir (n=415) 102 weeksb | Indinavir + ZDV/LAM (n=401) 76 weeksb | Efavirenza + Nelfinavir + NRTIs (n=64) 71.1 weeksb | Efavirenza + NRTIs (n=65) 70.9 weeksb | Nelfinavir + NRTIs (n=66) 62.7 weeksb |
| Chemistry | | | | | | | |
| ALT | >5 x ULN | 5% | 8% | 5% | 2% | 6% | 3% |
| AST | >5 x ULN | 5% | 6% | 5% | 6% | 8% | 8% |
| GGTc | >5 x ULN | 8% | 7% | 3% | 5% | 0 | 5% |
| Amylase | >2 x ULN | 4% | 4% | 1% | 0 | 6% | 2% |
| Glucose | >250 mg/dL | 3% | 3% | 3% | 5% | 2% | 3% |
| Triglyceridesd | ≥751 mg/dL | 9% | 6% | 6% | 11% | 8% | 17% |
| Hematology | | | | | | | |
| Neutrophils | <750/mm3 | 10% | 3% | 5% | 2% | 3% | 2% |
Patients Coinfected with Hepatitis B or C
Liver function tests should be monitored in patients with a history of hepatitis B and/or C. In the long-term data set from Study 006, 137 patients treated with efavirenz-containing regimens (median duration of therapy, 68 weeks) and 84 treated with a control regimen (median duration, 56 weeks) were seropositive at screening for hepatitis B (surface antigen positive) and/or C (hepatitis C antibody positive). Among these coinfected patients, elevations in AST to greater than five times ULN developed in 13% of patients in the efavirenz arms and 7% of those in the control arm, and elevations in ALT to greater than five times ULN developed in 20% of patients in the efavirenz arms and 7% of patients in the control arm. Among coinfected patients, 3% of those treated with efavirenz-containing regimens and 2% in the control arm discontinued from the study because of liver or biliary system disorders [see Warnings and Precautions (5.9)].
Lipids
Increases from baseline in total cholesterol of 10 to 20% have been observed in some uninfected volunteers receiving efavirenz. In patients treated with efavirenz + zidovudine + lamivudine, increases from baseline in nonfasting total cholesterol and HDL of approximately 20% and 25%, respectively, were observed. In patients treated with efavirenz + indinavir, increases from baseline in nonfasting cholesterol and HDL of approximately 40% and 35%, respectively, were observed. Nonfasting total cholesterol levels ≥240 mg/dL and ≥300 mg/dL were reported in 34% and 9%, respectively, of patients treated with efavirenz + zidovudine + lamivudine; 54% and 20%, respectively, of patients treated with efavirenz + indinavir; and 28% and 4%, respectively, of patients treated with indinavir + zidovudine + lamivudine. The effects of efavirenz on triglycerides and LDL in this study were not well characterized since samples were taken from nonfasting patients. The clinical significance of these findings is unknown [see Warnings and Precautions (5.11)].
Adverse Reactions in Pediatric Patients
Because clinical studies are conducted under widely varying conditions, the adverse reaction rates reported cannot be directly compared to rates in other clinical studies and may not reflect the rates observed in clinical practice.
Assessment of adverse reactions is based on three clinical trials in 182 HIV-1 infected pediatric patients (3 months to 21 years of age) who received efavirenz in combination with other antiretroviral agents for a median of 123 weeks. The adverse reactions observed in the three trials were similar to those observed in clinical trials in adults except that rash was more common in pediatric patients (32% for all grades regardless of causality) and more often of higher grade (i.e., more severe). Two (1.1%) pediatric patients experienced Grade 3 rash (confluent rash with fever, generalized rash), and four (2.2%) pediatric patients had Grade 4 rash (all erythema multiforme). Five pediatric patients (2.7%) discontinued from the study because of rash [see Warnings and Precautions (5.8)].
The following adverse reactions have been identified during postapproval use of efavirenz. Because these reactions are reported voluntarily from a population of unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Body as a Whole: allergic reactions, asthenia, redistribution/accumulation of body fat [see Warnings and Precautions (5.13)]
Central and Peripheral Nervous System: abnormal coordination, ataxia, encephalopathy, cerebellar coordination and balance disturbances, convulsions, hypoesthesia, paresthesia, neuropathy, tremor, vertigo
Endocrine: gynecomastia
Gastrointestinal: constipation, malabsorption
Cardiovascular: flushing, palpitations
Liver and Biliary System: hepatic enzyme increase, hepatic failure, hepatitis.
Metabolic and Nutritional: hypercholesterolemia, hypertriglyceridemia
Musculoskeletal: arthralgia, myalgia, myopathy
Psychiatric: aggressive reactions, agitation, delusions, emotional lability, mania, neurosis, paranoia, psychosis, suicide, catatonia
Respiratory: dyspnea
Skin and Appendages: erythema multiforme, photoallergic dermatitis, Stevens-Johnson syndrome
Special Senses: abnormal vision, tinnitus
Efavirenz has been shown in vivo to induce CYP3A and CYP2B6. Other compounds that are substrates of CYP3A or CYP2B6 may have decreased plasma concentrations when coadministered with efavirenz.
Drugs that induce CYP3A activity (e.g., phenobarbital, rifampin, rifabutin) would be expected to increase the clearance of efavirenz resulting in lowered plasma concentrations [see Dosage and Administration (2.2)].
There is limited information available on the potential for a pharmacodynamic interaction between efavirenz and drugs that prolong the QTc interval. QTc prolongation has been observed with the use of efavirenz [see Clinical Pharmacology (12.2)]. Consider alternatives to efavirenz when coadministered with a drug with a known risk of Torsade de Pointes.
Drug interactions with efavirenz are summarized in Table 5. For pharmacokinetics data, [see Clinical Pharmacology (12.3)] Tables 7 and 8. This table includes potentially significant interactions, but is not all inclusive.
| * The interaction between efavirenz and the drug was evaluated in a clinical study. All other drug interactions shown are predicted. | ||
| Concomitant Drug Class: Drug Name | Effect | Clinical Comment |
| HIV antiviral agents | | |
| Protease inhibitor: Fosamprenavir Calcium | ↓ amprenavir | Fosamprenavir (unboosted): Appropriate doses of the combinations with respect to safety and efficacy have not been established. Fosamprenavir/ritonavir: An additional 100 mg/day (300 mg total) of ritonavir is recommended when efavirenz is administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when efavirenz is administered with fosamprenavir plus ritonavir twice daily. |
| Protease inhibitor: Atazanavir | ↓ atazanavir* | Treatment-naive patients: When coadministered with efavirenz, the recommended dose of atazanavir is 400 mg with ritonavir 100 mg (together once daily with food) and efavirenz 600 mg (once daily on an empty stomach, preferably at bedtime). Treatment-experienced patients: Coadministration of efavirenz and atazanavir is not recommended. |
| Protease inhibitor: Indinavir | ↓ indinavir* | The optimal dose of indinavir, when given in combination with efavirenz, is not known. Increasing the indinavir dose to 1000 mg every 8 hours does not compensate for the increased indinavir metabolism due to efavirenz. |
| Protease inhibitor: Lopinavir/ritonavir | ↓ lopinavir* | Lopinavir/ritonavir once daily dosing is not recommended when coadministered with efavirenz. The dose of lopinavir/ritonavir must be increased when coadministered with efavirenz. See the lopinavir/ritonavir prescribing information for dose adjustments of lopinavir/ritonavir when coadministered with efavirenz in adult and pediatric patients. |
| Protease inhibitor: Ritonavir | ↑ ritonavir* ↑ efavirenz* | Monitor for elevation of liver enzymes and for adverse clinical experiences (e.g., dizziness, nausea, paresthesia) when efavirenz is coadministered with ritonavir. |
| Protease inhibitor: Saquinavir | ↓ saquinavir* | Appropriate doses of the combination of efavirenz and saquinavir/ritonavir with respect to safety and efficacy have not been established. |
| NNRTI: Other NNRTIs | ↑ or ↓ efavirenz and/or NNRTI | Combining two NNRTIs has not been shown to be beneficial. Efavirenz should not be coadministered with other NNRTIs. |
| CCR5 co-receptor antagonist: Maraviroc | ↓ maraviroc* | Refer to the full prescribing information for maraviroc for guidance on coadministration with efavirenz. |
| Hepatitis C antiviral agents | ||
| Boceprevir | ↓ boceprevir* | Concomitant administration of boceprevir with efavirenz is not recommended because it may result in loss of therapeutic effect of boceprevir. |
| Elbasvir/Grazoprevir | ↓ elbasvir ↓ grazoprevir | Coadministration of efavirenz with elbasvir/grazoprevir is contraindicated [see Contraindications (4)] because it may lead to loss of virologic response to elbasvir/grazoprevir. |
| Pibrentasvir/Glecaprevir | ↓ pibrentasvir ↓ glecaprevir | Coadministration of efavirenz is not recommended because it may lead to reduced therapeutic effect of pibrentasvir/glecaprevir. |
| Simeprevir | ↓ simeprevir* ↔ efavirenz* | Concomitant administration of simeprevir with efavirenz is not recommended because it may result in loss of therapeutic effect of simeprevir. |
| Velpatasvir/ Sofosbuvir | ↓ velpatasvir | Coadministration of efavirenz and sofosbuvir/velpatasvir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/velpatasvir. |
| Velpatasvir /Sofosbuvir/ Voxilaprevir | ↓ velpatasvir ↓ voxilaprevir | Coadministration of efavirenz and sofosbuvir/velpatasvir/voxilaprevir is not recommended because it may result in loss of therapeutic effect of sofosbuvir/ velpatasvir/voxilaprevir. |
| Other agents | | |
| Anticoagulant: Warfarin | ↑ or ↓ warfarin | Monitor INR and adjust warfarin dosage if necessary. |
| Anticonvulsants: Carbamazepine | ↓ carbamazepine* ↓ efavirenz* | There are insufficient data to make a dose recommendation for efavirenz. Alternative anticonvulsant treatment should be used. |
| Phenytoin Phenobarbital | ↓ anticonvulsant ↓ efavirenz | Potential for reduction in anticonvulsant and/or efavirenz plasma levels; periodic monitoring of anticonvulsant plasma levels should be conducted. |
| Antidepressants: Bupropion Sertraline | ↓ bupropion* ↓ sertraline* | Increases in bupropion dosage should be guided by clinical response. Bupropion dose should not exceed the maximum recommended dose. Increases in sertraline dosage should be guided by clinical response. |
| Antifungals: Voriconazole | ↓ voriconazole* ↑ efavirenz* | Efavirenz and voriconazole should not be coadministered at standard doses. When voriconazole is coadministered with efavirenz, voriconazole maintenance dose should be increased to 400 mg every 12 hours and efavirenz dose should be decreased to 300 mg once daily using the capsule formulation. Efavirenz tablets must not be broken. [See Dosage and Administration (2.2) and Clinical Pharmacology (12.3, Tables 7 and 8)]. |
| Itraconazole | ↓ itraconazole* ↓ hydroxyitraconazole* | Consider alternative antifungal treatment because no dose recommendation for itraconazole can be made. |
| Ketoconazole | ↓ ketoconazole | Consider alternative antifungal treatment because no dose recommendation for ketoconazole can be made. |
| Posaconazole | ↓ posaconazole* | Avoid concomitant use unless the benefit outweighs the risks. |
| Anti-infective: Clarithromycin | ↓ clarithromycin* ↑ 14-OH metabolite* | Consider alternatives to macrolide antibiotics because of the risk of QT interval prolongation. |
| Antimycobacterials: Rifabutin | ↓ rifabutin* | Increase daily dose of rifabutin by 50%. Consider doubling the rifabutin dose in regimens where rifabutin is given 2 or 3 times a week. |
| Rifampin | ↓ efavirenz* | Increase efavirenz to 800 mg once daily when coadministered with rifampin to patients weighing 50 kg or more. |
| Antimalarials: Artemether/ lumefantrine Atovaquone/proguanil | ↓ artemether* ↓ dihydroartemisinin* ↓ lumefantrine* ↓ atovaquone ↓ proguanil | Consider alternatives to artemether/lumefantrine because of the risk of QT interval prolongation. Concomitant administration is not recommended. |
| Calcium channel blockers: Diltiazem | ↓ diltiazem* ↓ desacetyl diltiazem* ↓ N-monodesmethyl diltiazem* | Diltiazem dose adjustments should be guided by clinical response (refer to the full prescribing information for diltiazem). No dose adjustment of efavirenz is necessary when administered with diltiazem. |
| Others (e.g., felodipine, nicardipine, nifedipine, verapamil) | ↓ calcium channel blocker | When coadministered with efavirenz, dosage adjustment of calcium channels blocker may be needed and should be guided by clinical response (refer to the full prescribing information for the calcium channel blocker). |
| HMG-CoA reductase inhibitors: Atorvastatin Pravastatin Simvastatin | ↓ atorvastatin* ↓ pravastatin* ↓ simvastatin* | Plasma concentrations of atorvastatin, pravastatin, and simvastatin decreased. Consult the full prescribing information for the HMG-CoA reductase inhibitor for guidance on individualizing the dose. |
| Hormonal contraceptives: Oral Ethinyl estradiol/ Norgestimate Implant Etonogestrel | ↓ active metabolites of norgestimate* ↓ etonogestrel | A reliable method of barrier contraception should be used in addition to hormonal contraceptives. A reliable method of barrier contraception should be used in addition to hormonal contraceptives. Decreased exposure of etonogestrel may be expected. There have been postmarketing reports of contraceptive failure with etonogestrel in efavirenz-exposed patients. |
| Immunosuppressants: Cyclosporine, tacrolimus, sirolimus, and others metabolized by CYP3A | ↓ immunosuppressant | Dose adjustments of the immunosuppressant may be required. Close monitoring of immunosuppressant concentrations for at least 2 weeks (until stable concentrations are reached) is recommended when starting or stopping treatment with efavirenz. |
| Narcotic analgesic: Methadone | ↓ methadone* | Monitor for signs of methadone withdrawal and increase methadone dose if required to alleviate withdrawal symptoms. |
This table is not all-inclusive.
No dosage adjustment is recommended when efavirenz is given with the following: aluminum/magnesium hydroxide antacids, azithromycin, cetirizine, famotidine, fluconazole, lorazepam, nelfinavir, nucleoside reverse transcriptase inhibitors (abacavir, emtricitabine, lamivudine, stavudine, tenofovir disoproxil fumarate, zidovudine), paroxetine, and raltegravir.
Efavirenz does not bind to cannabinoid receptors. False-positive urine cannabinoid test results have been reported with some screening assays in uninfected and HIV-infected subjects receiving efavirenz. Confirmation of positive screening tests for cannabinoids by a more specific method is recommended.
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to efavirenz during pregnancy. Physicians are encouraged to register patients by calling the Antiretroviral Pregnancy Registry at 1-800-258-4263.
Risk Summary
There are retrospective case reports of neural tube defects in infants whose mothers were exposed to efavirenz-containing regimens in the first trimester of pregnancy. Prospective pregnancy data from the Antiretroviral Pregnancy Registry are not sufficient to adequately assess this risk. Available data from the Antiretroviral Pregnancy Registry show no difference in the risk of overall major birth defects compared to the background rate for major birth defects of 2.7% in the U.S. reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). Although a causal relationship has not been established between exposure to efavirenz in the first trimester and neural tube defects, similar malformations have been observed in studies conducted in monkeys at doses similar to the human dose. In addition, fetal and embryonic toxicities occurred in rats, at a dose ten times less than the human exposure at recommended clinical dose. Because of the potential risk of neural tube defects, efavirenz should not be used in the first trimester of pregnancy. Advise pregnant women of the potential risk to a fetus.
Data
Human Data
There are retrospective postmarketing reports of findings consistent with neural tube defects, including meningomyelocele, all in infants of mothers exposed to efavirenz-containing regimens in the first trimester.
Based on prospective reports from the Antiretroviral Pregnancy Registry (APR) of approximately 1000 live births following exposure to efavirenz-containing regimens (including over 800 live births exposed in the first trimester), there was no difference between efavirenz and overall birth defects compared with the background birth defect rate of 2.7% in the U.S. reference population of the Metropolitan Atlanta Congenital Defects Program. As of the interim APR report issued December 2014, the prevalence of birth defects following first-trimester exposure was 2.3% (95% CI: 1.4% to 3.6%). One of these prospectively reported defects with first-trimester exposure was a neural tube defect. A single case of anophthalmia with first-trimester exposure to efavirenz has also been prospectively reported. This case also included severe oblique facial clefts and amniotic banding, which have a known association with anophthalmia.
Animal Data
Effects of efavirenz on embryo-fetal development have been studied in three nonclinical species (cynomolgus monkeys, rats, and rabbits). In monkeys, efavirenz 60 mg/kg/day was administered to pregnant females throughout pregnancy (gestation days 20 through 150). The maternal systemic drug exposures (AUC) were 1.3 times the exposure in humans at the recommended clinical dose (600 mg/day), with fetal umbilical venous drug concentrations approximately 0.7 times the maternal values. Three of 20 fetuses/infants had one or more malformations; there were no malformed fetuses or infants from placebo-treated mothers. The malformations that occurred in these three monkey fetuses included anencephaly and unilateral anophthalmia in one fetus, microphthalmia in a second, and cleft palate in the third. There was no NOAEL (no observable adverse effect level) established for this study because only one dosage was evaluated. In rats, efavirenz was administered either during organogenesis (gestation days 7 to 18) or from gestation day 7 through lactation day 21 at 50, 100, or 200 mg/kg/day. Administration of 200 mg/kg/day in rats was associated with increase in the incidence of early resorptions; and doses 100 mg/kg/day and greater were associated with early neonatal mortality. The AUC at the NOAEL (50 mg/kg/day) in this rat study was 0.1 times that in humans at the recommended clinical dose. Drug concentrations in the milk on lactation day 10 were approximately 8 times higher than those in maternal plasma. In pregnant rabbits, efavirenz was neither embryo lethal nor teratogenic when administered at doses of 25, 50, and 75 mg/kg/day over the period of organogenesis (gestation days 6 through 18). The AUC at the NOAEL (75 mg/kg/day) in rabbits was 0.4 times that in humans at the recommended clinical dose.
Risk Summary
The Centers for Disease Control and Prevention recommend that HIV-infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV. Because of the potential for HIV transmission in breastfed infants, advise women not to breastfeed.
Because of potential teratogenic effects, pregnancy should be avoided in women receiving efavirenz. [See Use in Specific Populations (8.1)].
Pregnancy Testing
Females of reproductive potential should undergo pregnancy testing before initiation of efavirenz.
Contraception
Females of reproductive potential should use effective contraception during treatment with efavirenz and for 12 weeks after discontinuing efavirenz due to the long half-life of efavirenz. Barrier contraception should always be used in combination with other methods of contraception. Hormonal methods that contain progesterone may have decreased effectiveness [see Drug Interactions (7.1)].
The safety, pharmacokinetic profile, and virologic and immunologic responses of efavirenz were evaluated in antiretroviral-naive and -experienced HIV-1 infected pediatric patients 3 months to 21 years of age in three open-label clinical trials [see Adverse Reactions (6.2), Clinical Pharmacology (12.3), and Clinical Studies (14.2)]. The type and frequency of adverse reactions in these trials were generally similar to those of adult patients with the exception of a higher frequency of rash, including a higher frequency of Grade 3 or 4 rash, in pediatric patients compared to adults [see Warnings and Precautions (5.8) and Adverse Reactions (6.2)].
Use of efavirenz in patients younger than 3 months of age OR less than 3.5 kg body weight is not recommended because the safety, pharmacokinetics, and antiviral activity of efavirenz have not been evaluated in this age group and there is a risk of developing HIV resistance if efavirenz is underdosed. See Dosage and Administration (2.2) for dosing recommendations for pediatric patients.
Clinical studies of efavirenz did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other therapy.
Efavirenz is not recommended for patients with moderate or severe hepatic impairment because there are insufficient data to determine whether dose adjustment is necessary. Patients with mild hepatic impairment may be treated with efavirenz without any adjustment in dose. Because of the extensive cytochrome P450-mediated metabolism of efavirenz and limited clinical experience in patients with hepatic impairment, caution should be exercised in administering efavirenz to these patients [see Warnings and Precautions (5.9) and Clinical Pharmacology (12.3)].
Some patients accidentally taking 600 mg twice daily have reported increased nervous system symptoms. One patient experienced involuntary muscle contractions.
Treatment of overdose with efavirenz should consist of general supportive measures, including monitoring of vital signs and observation of the patient’s clinical status. Administration of activated charcoal may be used to aid removal of unabsorbed drug. There is no specific antidote for overdose with efavirenz. Since efavirenz is highly protein bound, dialysis is unlikely to significantly remove the drug from blood.
Efavirenz is an HIV-1 specific, non-nucleoside, reverse transcriptase inhibitor (NNRTI). Efavirenz is chemically described as (S)-6-chloro-4-(cyclopropylethynyl)-1,4-dihydro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one. Its molecular formula is C14H9ClF3NO2 and its structural formula is:
Chemical Structure (Efavirenz Str)
Efavirenz USP is a white to off-white, crystalline powder with a molecular mass of 315.68. It is practically insoluble in water (<10 microgram/mL).
Efavirenz is available as film-coated tablets for oral administration containing 600 mg of efavirenz USP and the following inactive ingredients: croscarmellose sodium, hydroxypropyl cellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium lauryl sulfate. The film coating contains hypromellose, polyethylene glycol, titanium dioxide, and yellow iron oxide.
Efavirenz is an antiviral drug [see Microbiology (12.4)].
Cardiac Electrophysiology
The effect of efavirenz on the QTc interval was evaluated in an open-label, positive and placebo controlled, fixed single sequence 3-period, 3-treatment crossover QT study in 58 healthy subjects enriched for CYP2B6 polymorphisms. The mean Cmax of efavirenz in subjects with CYP2B6 *6/*6 genotype following the administration of 600 mg daily dose for 14 days was 2.25-fold the mean Cmax observed in subjects with CYP2B6 *1/*1 genotype. A positive relationship between efavirenz concentration and QTc prolongation was observed. Based on the concentration-QTc relationship, the mean QTc prolongation and its upper bound 90% confidence interval are 8.7 ms and 11.3 ms in subjects with CYP2B6*6/*6 genotype following the administration of 600 mg daily dose for 14 days [see Warnings and Precautions (5.2)].
Absorption
Peak efavirenz plasma concentrations of 1.6 to 9.1 µM were attained by 5 hours following single oral doses of 100 mg to 1600 mg administered to uninfected volunteers. Dose-related increases in Cmax and AUC were seen for doses up to 1600 mg; the increases were less than proportional suggesting diminished absorption at higher doses.
In HIV-1-infected patients at steady state, mean Cmax, mean Cmin, and mean AUC were dose proportional following 200 mg, 400 mg, and 600 mg daily doses. Time-to-peak plasma concentrations were approximately 3 to 5 hours and steady-state plasma concentrations were reached in 6 to 10 days. In 35 patients receiving efavirenz 600 mg once daily, steady-state Cmax was 12.9 ± 3.7 µM (mean ± SD), steady-state Cmin was 5.6 ± 3.2 µM, and AUC was 184 ± 73 µM•h.
Effect of Food on Oral Absorption:
Capsules:Administration of a single 600 mg dose of efavirenz capsules with a high-fat/high-caloric meal (894 kcal, 54 g fat, 54% calories from fat) or a reduced-fat/normal-caloric meal (440 kcal, 2 g fat, 4% calories from fat) was associated with a mean increase of 22% and 17% in efavirenz AUC∞and a mean increase of 39% and 51% in efavirenz Cmax, respectively, relative to the exposures achieved when given under fasted conditions. [See Dosage and Administration (2) and Patient Counseling Information (17).]
Tablets: Administration of a single 600 mg efavirenz tablet with a high-fat/high-caloric meal (approximately 1000 kcal, 500 to 600 kcal from fat) was associated with a 28% increase in mean AUC∞ of efavirenz and a 79% increase in mean Cmax of efavirenz relative to the exposures achieved under fasted conditions. [See Dosage and Administration (2) and Patient Counseling Information (17)].
Bioavailability of capsule contents mixed with food vehicles: In healthy adult subjects, the efavirenz AUC when administered as the contents of three 200 mg capsules mixed with 2 teaspoons of certain food vehicles (applesauce, grape jelly or yogurt, or infant formula) met bioequivalency criteria for the AUC of the intact capsule formulation administered under fasted conditions.
Distribution
Efavirenz is highly bound (approximately 99.5 to 99.75%) to human plasma proteins, predominantly albumin. In HIV-1 infected patients (n=9) who received efavirenz 200 to 600 mg once daily for at least one month, cerebrospinal fluid concentrations ranged from 0.26 to 1.19% (mean 0.69%) of the corresponding plasma concentration. This proportion is approximately 3-fold higher than the non-protein-bound (free) fraction of efavirenz in plasma.
Metabolism
Studies in humans and in vitro studies using human liver microsomes have demonstrated that efavirenz is principally metabolized by the cytochrome P450 system to hydroxylated metabolites with subsequent glucuronidation of these hydroxylated metabolites. These metabolites are essentially inactive against HIV-1. The in vitro studies suggest that CYP3A and CYP2B6 are the major isozymes responsible for efavirenz metabolism.
Efavirenz has been shown to induce CYP enzymes, resulting in the induction of its own metabolism. Multiple doses of 200 to 400 mg per day for 10 days resulted in a lower than predicted extent of accumulation (22 to 42% lower) and a shorter terminal half-life of 40 to 55 hours (single dose half-life 52 to 76 hours).
Elimination
Efavirenz has a terminal half-life of 52 to 76 hours after single doses and 40 to 55 hours after multiple doses. A one-month mass balance/excretion study was conducted using 400 mg per day with a 14C-labeled dose administered on Day 8. Approximately 14 to 34% of the radiolabel was recovered in the urine and 16 to 61% was recovered in the feces. Nearly all of the urinary excretion of the radiolabeled drug was in the form of metabolites. Efavirenz accounted for the majority of the total radioactivity measured in feces.
Special Populations
Pediatric: The pharmacokinetic parameters for efavirenz at steady state in pediatric patients were predicted by a population pharmacokinetic model and are summarized in Table 6 by weight ranges that correspond to the recommended doses.
| Body Weight | Dose | Mean AUC(0-24) µM·h | Mean Cmax mcg/mL | Mean Cmin mcg/mL |
| 3.5 to 5 kg | 100 mg | 220.52 | 5.81 | 2.43 |
| 5 to 7.5 kg | 150 mg | 262.62 | 7.07 | 2.71 |
| 7.5 to 10 kg | 200 mg | 284.28 | 7.75 | 2.87 |
| 10 to 15 kg | 200 mg | 238.14 | 6.54 | 2.32 |
| 15 to 20 kg | 250 mg | 233.98 | 6.47 | 2.3 |
| 20 to 25 kg | 300 mg | 257.56 | 7.04 | 2.55 |
| 25 to 32.5 kg | 350 mg | 262.37 | 7.12 | 2.68 |
| 32.5 to 40 kg | 400 mg | 259.79 | 6.96 | 2.69 |
| >40 kg | 600 mg | 254.78 | 6.57 | 2.82 |
Gender and race: The pharmacokinetics of efavirenz in patients appear to be similar between men and women and among the racial groups studied.
Renal impairment: The pharmacokinetics of efavirenz have not been studied in patients with renal insufficiency; however, less than 1% of efavirenz is excreted unchanged in the urine, so the impact of renal impairment on efavirenz elimination should be minimal.
Hepatic impairment: A multiple-dose study showed no significant effect on efavirenz pharmacokinetics in patients with mild hepatic impairment (Child-Pugh Class A) compared with controls. There were insufficient data to determine whether moderate or severe hepatic impairment (Child-Pugh Class B or C) affects efavirenz pharmacokinetics.
Drug Interaction Studies
Efavirenz has been shown in vivo to cause hepatic enzyme induction, thus increasing the biotransformation of some drugs metabolized by CYP3A and CYP2B6. In vitro studies have shown that efavirenz inhibited CYP isozymes 2C9 and 2C19 with Ki values (8.5 to 17 μM) in the range of observed efavirenz plasma concentrations. In in vitro studies, efavirenz did not inhibit CYP2E1 and inhibited CYP2D6 and CYP1A2 (Ki values 82 to 160 μM) only at concentrations well above those achieved clinically. Coadministration of efavirenz with drugs primarily metabolized by CYP2C9, CYP2C19, CYP3A, or CYP2B6 isozymes may result in altered plasma concentrations of the coadministered drug. Drugs which induce CYP3A and CYP2B6 activity would be expected to increase the clearance of efavirenz resulting in lowered plasma concentrations.
Drug interaction studies were performed with efavirenz and other drugs likely to be coadministered or drugs commonly used as probes for pharmacokinetic interaction. The effects of coadministration of efavirenz on the Cmax, AUC, and Cmin are summarized in Table 7 (effect of efavirenz on other drugs) and Table 8 (effect of other drugs on efavirenz). For information regarding clinical recommendations see Drug Interactions (7.1).
| Coadministered Drug | Dose | Efavirenz Dose | Number of Subjects | Coadministered Drug (mean % change) | ||
|---|---|---|---|---|---|---|
| Cmax (90% CI) | AUC (90% CI) | Cmin (90% CI) | ||||
| ↑ Indicates increase ↓ Indicates decrease ↔ Indicates no change or a mean increase or decrease of <10%. a Compared with atazanavir 400 mg qd alone. b Comparator dose of indinavir was 800 mg q 8 h x 10 days. c Parallel-group design; n for efavirenz + lopinavir/ritonavir, n for lopinavir/ritonavir alone. d Values are for lopinavir; the pharmacokinetics of ritonavir in this study were unaffected by concurrent efavirenz. e 95% CI. f Soft Gelatin Capsule. g Tenofovir disoproxil fumarate. h 90% CI not available. i Relative to steady-state administration of voriconazole (400 mg for 1 day, then 200 mg po q 12 h for 2 days). j Not available because of insufficient data. NA = not available. | ||||||
| Atazanavir | 400 mg qd with a light meal d 1 to 20 | 600 mg qd with a light meal d 7 to 20 | 27 | ↓ 59% (49 to 67%) | ↓ 74% (68 to 78%) | ↓ 93% (90 to 95%) |
| 400 mg qd d 1 to 6, then 300 mg qd d 7 to 20 with ritonavir 100 mg qd and a light meal | 600 mg qd 2 h after atazanavir and ritonavir d 7 to 20 | 13 | ↑ 14%a (↓ 17 to ↑ 58%) | ↑ 39%a (2 to 88%) | ↑ 48%a (24 to 76%) | |
| 300 mg qd/ritonavir 100 mg qd d 1 to 10 (pm), then 400 mg qd/ritonavir 100 mg qd d 11 to 24 (pm) (simultaneous with efavirenz) | 600 mg qd with a light snack d 11 to 24 (pm) | 14 | ↑ 17% (8 to 27%) | ↔ | ↓ 42% (31 to 51%) | |
| Indinavir | 1000 mg q 8 h x 10 days | 600 mg qd x 10 days | 20 | | | |
| | After morning dose | | | ↔b | ↓ 33%b (26 to 39%) | ↓ 39%b (24 to 51%) |
| | After afternoon dose | | | ↔b | ↓ 37%b (26 to 46%) | ↓ 52%b (47 to 57%) |
| | After evening dose | | | ↓ 29%b (11 to 43%) | ↓ 46%b (37 to 54%) | ↓ 57%b (50 to 63%) |
| Lopinavir/ ritonavir | 400/100 mg capsule q 12 h × 9 days | 600 mg qd x 9 days | 11,7c | ↔d | ↓ 19%d (↓ 36 to ↑3%) | ↓ 39%d (3 to 62%) |
| | 500/125 mg tablet q 12 h × 10 days with efavirenz compared to 400/100 mg q 12 h alone | 600 mg qd x 9 days | 19 | ↑ 12%d (2 to 23%) | ↔d | ↓ 10%d (↓22 to ↑4%) |
| | 600/150 mg tablet q 12 h x 10 days with efavirenz compared to 400/100 mg q 12 h alone | 600 mg qd x 9 days | 23 | ↑ 36%d (28 to 44%) | ↑ 36%d (28 to 44%) | ↑ 32%d (21 to 44%) |
| Nelfinavir | 750 mg q 8 h x 7 days | 600 mg qd x 7 days | 10 | ↑ 21% (10 to 33%) | ↑ 20% (8 to 34%) | ↔ |
| Metabolite AG-1402 | | | | ↓ 40% (30 to 48%) | ↓ 37% (25 to 48%) | ↓ 43% (21 to 59%) |
| Ritonavir | 500 mg q 12 h x 8 days | 600 mg qd x 10 days | 11 | | | |
| | After AM dose | | | ↑ 24% (12 to 38%) | ↑ 18% (6 to 33%) | ↑ 42% (9 to 86%)e |
| | After PM dose | | | ↔ | ↔ | ↑ 24% (3 to 50%)e |
| Saquinavir | 1200 mg q 8 h x 10 days | 600 mg qd x 10 days | 12 | ↓ 50% (28 to 66%) | ↓ 62% (45 to 74%) | ↓ 56% (16 to 77%)e |
| SGCf | ||||||
| Lamivudine | 150 mg q 12 h x 14 days | 600 mg qd x 14 days | 9 | ↔ | ↔ | ↑ 265% (37 to 873%) |
| Tenofovirg | 300 mg qd | 600 mg qd x 14 days | 29 | ↔ | ↔ | ↔ |
| Zidovudine | 300 mg q 12 h x 14 days | 600 mg qd x 14 days | 9 | ↔ | ↔ | ↑ 225% (43 to 640%) |
| Maraviroc | 100 mg bid | 600 mg qd | 12 | ↓ 51% (37 to 62%) | ↓ 45% (38 to 51%) | ↓ 45% (28 to 57%) |
| Raltegravir | 400 mg single dose | 600 mg qd | 9 | ↓ 36% (2 to 59%) | ↓ 36% (20 to 48%) | ↓ 21% (↓ 51 to ↑ 28%) |
| Boceprevir | 800 mg tid x 6 days | 600 mg qd x 16 days | NA | ↓ 8% (↓ 22 to ↑ 8%) | ↓ 19% (11 to 25%) | ↓ 44% (26 to 58%) |
| Simeprevir | 150 mg qd x 14 days | 600 mg qd x 14 days | 23 | ↓ 51% (↓ 46 to ↓ 56%) | ↓ 71% (↓ 67 to ↓ 74%) | ↓ 91% (↓ 88 to ↓ 92%) |
| Azithromycin | 600 mg single dose | 400 mg qd x 7 days | 14 | ↑ 22% (4 to 42%) | ↔ | NA |
| Clarithromycin | 500 mg q 12 h x 7 days | 400 mg qd x 7 days | 11 | ↓ 26% (15 to 35%) | ↓ 39% (30 to 46%) | ↓ 53% (42 to 63%) |
| 14-OH metabolite | | | | ↑ 49% (32 to 69%) | ↑ 34% (18 to 53%) | ↑ 26% (9 to 45%) |
| Fluconazole | 200 mg x 7 days | 400 mg qd x 7 days | 10 | ↔ | ↔ | ↔ |
| Itraconazole | 200 mg q 12 h x 28 days | 600 mg qd x 14 days | 18 | ↓ 37% (20 to 51%) | ↓ 39% (21 to 53%) | ↓ 44% (27 to 58%) |
| Hydroxy-itraconazole | | | | ↓ 35% (12 to 52%) | ↓ 37% (14 to 55%) | ↓ 43% (18 to 60%) |
| Posaconazole | 400 mg (oral suspension) bid x 10 and 20 days | 400 mg qd x 10 and 20 days | 11 | ↓ 45% (34 to 53%) | ↓ 50% (40 to 57%) | NA |
| Rifabutin | 300 mg qd x 14 days | 600 mg qd x 14 days | 9 | ↓ 32% (15 to 46%) | ↓ 38% (28 to 47%) | ↓ 45% (31 to 56%) |
| Voriconazole | 400 mg po q 12 h x 1 day, then 200 mg po q 12 h x 8 days | 400 mg qd x 9 days | NA | ↓ 61%h | ↓ 77%h | NA |
| | 300 mg po q 12 h days 2 to 7 | 300 mg qd x 7 days | NA | ↓ 36%i (21 to 49%) | ↓ 55%i (45 to 62%) | NA |
| | 400 mg po q 12 h days 2 to 7 | 300 mg qd x 7 days | NA | ↑ 23%i (↓ 1 to ↑ 53%) | ↓ 7%i (↓ 23 to ↑ 13%) | NA |
| Artemether/ lumefantrine | Artemether 20 mg/ lumefantrine 120 mg tablets (6 4-tablet doses over 3 days) | 600 mg qd × 26 days | 12 | | | |
| Artemether | | | | ↓ 21% | ↓ 51% | NA |
| dihydroartemisinin | | | | ↓ 38% | ↓ 46% | NA |
| Lumefantrine | | | | ↔ | ↓ 21% | NA |
| Atorvastatin | 10 mg qd x 4 days | 600 mg qd x 15 days | 14 | ↓ 14% (1 to 26%) | ↓ 43% (34 to 50%) | ↓ 69% (49 to 81%) |
| Total active (including metabolites) | | | | ↓ 15% (2 to 26%) | ↓ 32% (21 to 41%) | ↓ 48% (23 to 64%) |
| Pravastatin | 40 mg qd x 4 days | 600 mg qd x 15 days | 13 | ↓ 32% (↓ 59 to ↑ 12%) | ↓ 44% (26 to 57%) | ↓ 19% (0 to 35%) |
| Simvastatin | 40 mg qd x 4 days | 600 mg qd x 15 days | 14 | ↓ 72% (63 to 79%) | ↓ 68% (62 to 73%) | ↓ 45% (20 to 62%) |
| Total active (including metabolites) | | | | ↓ 68% (55 to 78%) | ↓ 60% (52 to 68%) | NAj |
| Carbamazepine Epoxide metabolite | 200 mg qd x 3 days, 200 mg bid x 3 days, then 400 mg qd x 29 days | 600 mg qd x 14 days | 12 | ↓ 20% (15 to 24%) | ↓ 27% (20 to 33%) | ↓ 35% (24 to 44%) |
| | | | ↔ | ↔ | ↓ 13% (↓ 30 to ↑ 7%) | |
| Cetirizine | 10 mg single dose | 600 mg qd x 10 days | 11 | ↓ 24% (18 to 30%) | ↔ | NA |
| Diltiazem | 240 mg x 21 days | 600 mg qd x 14 days | 13 | ↓ 60% (50 to 68%) | ↓ 69% (55 to 79%) | ↓ 63% (44 to 75%) |
| Desacetyl diltiazem | | | | ↓ 64% (57 to 69%) | ↓ 75% (59 to 84%) | ↓ 62% (44 to 75%) |
| N-monodesmethyl diltiazem | | | | ↓ 28% (7 to 44%) | ↓ 37% (17 to 52%) | ↓ 37% (17 to 52%) |
| Ethinyl estradiol/ Norgestimate Ethinyl estradiol Norelgestromin Levonorgestrel | 0.035 mg/0.25 mg x 14 days | 600 mg qd x 14 days | 21 21 6 | ↔ ↓ 46% (39 to 52%) ↓ 80% (77 to 83%) | ↔ ↓ 64% (62 to 67%) ↓ 83% (79 to 87%) | ↔ ↓ 82% (79 to 85%) ↓ 86% (80 to 90%) |
| Lorazepam | 2 mg single dose | 600 mg qd x 10 days | 12 | ↑ 16% (2 to 32%) | ↔ | NA |
| Methadone | Stable maintenance 35 to 100 mg daily | 600 mg qd x 14 to 21 days | 11 | ↓ 45% (25 to 59%) | ↓ 52% (33 to 66%) | NA |
| Bupropion Hydroxy-bupropion | 150 mg single dose (sustained-release) | 600 mg qd x 14 days | 13 | ↓ 34% (21 to 47%) ↑ 50% (20 to 80%) | ↓ 55% (48 to 62%) ↔ | NA NA |
| Paroxetine | 20 mg qd x 14 days | 600 mg qd x 14 days | 16 | ↔ | ↔ | ↔ |
| Sertraline | 50 mg qd x 14 days | 600 mg qd x 14 days | 13 | ↓ 29% (15 to 40%) | ↓ 39% (27 to 50%) | ↓ 46% (31 to 58%) |
| | Efavirenz (mean % change) | |||||
|---|---|---|---|---|---|---|
| Coadministered Drug | Dose | Efavirenz Dose | Number of Subjects | Cmax (90% CI) | AUC (90% CI) | Cmin (90% CI) |
| ↑ Indicates increase ↓ Indicates decrease ↔ Indicates no change or a mean increase or decrease of <10%. a Parallel-group design; n for efavirenz + lopinavir/ritonavir, n for efavirenz alone. b 95% CI. c Soft Gelatin Capsule. d Tenofovir disoproxil fumarate. e 90% CI not available. f Relative to steady-state administration of efavirenz (600 mg once daily for 9 days). NA = not available. | ||||||
| Indinavir | 800 mg q 8 h x 14 days | 200 mg qd x 14 days | 11 | ↔ | ↔ | ↔ |
| Lopinavir/ ritonavir | 400/100 mg q 12 h x 9 days | 600 mg qd x 9 days | 11,12a | ↔ | ↓ 16% (↓ 38 to ↑ 15%) | ↓ 16% (↓ 42 to ↑ 20%) |
| Nelfinavir | 750 mg q 8 h x 7 days | 600 mg qd x 7 days | 10 | ↓ 12% (↓ 32 to ↑ 13%)b | ↓ 12% (↓ 35 to ↑ 18%)b | ↓ 21% (↓ 53 to ↑ 33%) |
| Ritonavir | 500 mg q 12 h x 8 days | 600 mg qd x 10 days | 9 | ↑ 14% (4 to 26%) | ↑ 21% (10 to 34%) | ↑ 25% (7 to 46%)b |
| Saquinavir SGCc | 1200 mg q 8 h x 10 days | 600 mg qd x 10 days | 13 | ↓ 13% (5 to 20%) | ↓ 12% (4 to 19%) | ↓ 14% (2 to 24%)b |
| Tenofovird | 300 mg qd | 600 mg qd x 14 days | 30 | ↔ | ↔ | ↔ |
| Boceprevir | 800 mg tid x 6 days | 600 mg qd x 16 days | NA | ↑ 11% (2 to 20%) | ↑ 20% (15 to 26%) | NA |
| Simeprevir | 150 mg qd x 14 days | 600 mg qd x 14 days | 23 | ↔ | ↓ 10% (5 to 15%) | ↓ 13% (7 to 19%) |
| Azithromycin | 600 mg single dose | 400 mg qd x 7 days | 14 | ↔ | ↔ | ↔ |
| Clarithromycin | 500 mg q 12 h x 7 days | 400 mg qd x 7 days | 12 | ↑ 11% (3 to 19%) | ↔ | ↔ |
| Fluconazole | 200 mg x 7 days | 400 mg qd x 7 days | 10 | ↔ | ↑ 16% (6 to 26%) | ↑ 22% (5 to 41%) |
| Itraconazole | 200 mg q 12 h x 14 days | 600 mg qd x 28 days | 16 | ↔ | ↔ | ↔ |
| Rifabutin | 300 mg qd x 14 days | 600 mg qd x 14 days | 11 | ↔ | ↔ | ↓ 12% (↓ 24 to ↑ 1%) |
| Rifampin | 600 mg x 7 days | 600 mg qd x 7 days | 12 | ↓ 20% (11 to 28%) | ↓ 26% (15 to 36%) | ↓ 32% (15 to 46%) |
| Voriconazole | 400 mg po q 12 h x 1 day, then 200 mg po q l2 h x 8 days | 400 mg qd x 9 days | NA | ↑ 38%e | ↑ 44%e | NA |
| | 300 mg po q 12 h days 2 to 7 | 300 mg qd x 7 days | NA | ↓ 14%f (7 to 21%) | ↔f | NA |
| | 400 mg po q 12 h days 2 to 7 | 300 mg qd x 7 days | NA | ↔f | ↑ 17%f (6 to 29%) | NA |
| Artemether/ Lumefantrine | Artemether 20 mg/ lumefantrine 120 mg tablets (6 4-tablet doses over 3 days) | 600 mg qd × 26 days | 12 | ↔ | ↓ 17% | NA |
| Atorvastatin | 10 mg qd x 4 days | 600 mg qd x 15 days | 14 | ↔ | ↔ | ↔ |
| Pravastatin | 40 mg qd x 4 days | 600 mg qd x 15 days | 11 | ↔ | ↔ | ↔ |
| Simvastatin | 40 mg qd x 4 days | 600 mg qd x 15 days | 14 | ↓ 12% (↓ 28 to ↑ 8%) | ↔ | ↓ 12% (↓ 25 to ↑ 3%) |
| Aluminum hydroxide 400 mg, magnesium hydroxide 400 mg, plus simethicone 40 mg | 30 mL single dose | 400 mg single dose | 17 | ↔ | ↔ | NA |
| Carbamazepine | 200 mg qd x 3 days, 200 mg bid x 3 days, then 400 mg qd x 15 days | 600 mg qd x 35 days | 14 | ↓ 21% (15 to 26%) | ↓ 36% (32 to 40%) | ↓ 47% (41 to 53%) |
| Cetirizine | 10 mg single dose | 600 mg qd x 10 days | 11 | ↔ | ↔ | ↔ |
| Diltiazem | 240 mg x 14 days | 600 mg qd x 28 days | 12 | ↑ 16% (6 to 26%) | ↑ 11% (5 to 18%) | ↑ 13% (1 to 26%) |
| Famotidine | 40 mg single dose | 400 mg single dose | 17 | ↔ | ↔ | NA |
| Paroxetine | 20 mg qd x 14 days | 600 mg qd x 14 days | 12 | ↔ | ↔ | ↔ |
| Sertraline | 50 mg qd x 14 days | 600 mg qd x 14 days | 13 | ↑ 11% (6 to 16%) | ↔ | ↔ |
Mechanism of Action
Efavirenz is an NNRTI of HIV-1. Efavirenz activity is mediated predominantly by noncompetitive inhibition of HIV-1 reverse transcriptase. HIV-2 reverse transcriptase and human cellular DNA polymerases α, β, γ, and δ are not inhibited by efavirenz.
Antiviral Activity in Cell Culture
The concentration of efavirenz inhibiting replication of wild-type laboratory adapted strains and clinical isolates in cell culture by 90 to 95% (EC90-95) ranged from 1.7 to 25 nM in lymphoblastoid cell lines, peripheral blood mononuclear cells (PBMCs), and macrophage/monocyte cultures. Efavirenz demonstrated antiviral activity against clade B and most non-clade B isolates (subtypes A, AE, AG, C, D, F, G, J, N), but had reduced antiviral activity against group O viruses. Efavirenz demonstrated additive antiviral activity without cytotoxicity against HIV-1 in cell culture when combined with the NNRTIs delavirdine and nevirapine, NRTIs (abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zalcitabine, zidovudine), PIs (amprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir), and the fusion inhibitor enfuvirtide. Efavirenz demonstrated additive to antagonistic antiviral activity in cell culture with atazanavir. Efavirenz was not antagonistic with adefovir, used for the treatment of hepatitis B virus infection, or ribavirin, used in combination with interferon for the treatment of hepatitis C virus infection.
Resistance
In cell culture
In cell culture, HIV-1 isolates with reduced susceptibility to efavirenz (>380-fold increase in EC90 value) emerged rapidly in the presence of drug. Genotypic characterization of these viruses identified single amino acid substitutions L100I or V179D, double substitutions L100I/V108I, and triple substitutions L100I/V179D/Y181C in reverse transcriptase.
Clinical studies
Clinical isolates with reduced susceptibility in cell culture to efavirenz have been obtained. One or more substitutions at amino acid positions 98, 100, 101, 103, 106, 108, 188, 190, 225, and 227 in reverse transcriptase were observed in patients failing treatment with efavirenz in combination with indinavir, or with zidovudine plus lamivudine. The K103N substitution was the most frequently observed. Long-term resistance surveillance (average 52 weeks, range 4 to 106 weeks) analyzed 28 matching baseline and virologic failure isolates. Sixty-one percent (17/28) of these failure isolates had decreased efavirenz susceptibility in cell culture with a median 88-fold change in efavirenz susceptibility (EC50 value) from reference. The most frequent NNRTI substitution to develop in these patient isolates was K103N (54%). Other NNRTI substitutions that developed included L100I (7%), K101E/Q/R (14%), V108I (11%), G190S/T/A (7%), P225H (18%), and M230I/L (11%).
Cross-Resistance
Cross-resistance among NNRTIs has been observed. Clinical isolates previously characterized as efavirenz-resistant were also phenotypically resistant in cell culture to delavirdine and nevirapine compared to baseline. Delavirdine- and/or nevirapine-resistant clinical viral isolates with NNRTI resistance-associated substitutions (A98G, L100I, K101E/P, K103N/S, V106A, Y181X, Y188X, G190X, P225H, F227L, or M230L) showed reduced susceptibility to efavirenz in cell culture. Greater than 90% of NRTI-resistant clinical isolates tested in cell culture retained susceptibility to efavirenz.
Carcinogenesis
Long-term carcinogenicity studies in mice and rats were carried out with efavirenz. Mice were dosed with 0, 25, 75, 150, or 300 mg/kg/day for 2 years. Incidences of hepatocellular adenomas and carcinomas and pulmonary alveolar/bronchiolar adenomas were increased above background in females. No increases in tumor incidence above background were seen in males. There was no NOAEL in females established for this study because tumor findings occurred at all doses. AUC at the NOAEL (150 mg/kg) in the males was approximately 0.9 times that in humans at the recommended clinical dose. In the rat study, no increases in tumor incidence were observed at doses up to 100 mg/kg/day, for which AUCs were 0.1 (males) or 0.2 (females) times those in humans at the recommended clinical dose.
Mutagenesis
Efavirenz tested negative in a battery of in vitro and in vivo genotoxicity assays. These included bacterial mutation assays in S. typhimurium and E. coli, mammalian mutation assays in Chinese hamster ovary cells, chromosome aberration assays in human peripheral blood lymphocytes or Chinese hamster ovary cells, and an in vivo mouse bone marrow micronucleus assay.
Impairment of Fertility
Efavirenz did not impair mating or fertility of male or female rats, and did not affect sperm of treated male rats. The reproductive performance of offspring born to female rats given efavirenz was not affected. The AUCs at the NOAEL values in male (200 mg/kg) and female (100 mg/kg) rats were approximately ≤0.15 times that in humans at the recommended clinical dose.
Nonsustained convulsions were observed in 6 of 20 monkeys receiving efavirenz at doses yielding plasma AUC values 4- to 13-fold greater than those in humans given the recommended dose [see Warnings and Precautions (5.10)].
Study 006, a randomized, open-label trial, compared efavirenz (600 mg once daily) + zidovudine (ZDV, 300 mg q 12 h) + lamivudine (LAM, 150 mg q 12 h) or efavirenz (600 mg once daily) + indinavir (IDV, 1000 mg q 8 h) with indinavir (800 mg q 8 h) + zidovudine (300 mg q 12 h) + lamivudine (150 mg q 12 h). Twelve hundred sixty-six patients (mean age 36.5 years [range 18 to 81], 60% Caucasian, 83% male) were enrolled. All patients were efavirenz-, lamivudine-, NNRTI-, and PI-naive at study entry. The median baseline CD4+ cell count was 320 cells/mm3 and the median baseline HIV-1 RNA level was 4.8 log10 copies/mL. Treatment outcomes with standard assay (assay limit 400 copies/mL) through 48 and 168 weeks are shown in Table 9. Plasma HIV RNA levels were quantified with standard (assay limit 400 copies/mL) and ultrasensitive (assay limit 50 copies/mL) versions of the AMPLICOR HIV-1 MONITOR assay. During the study, version 1.5 of the assay was introduced in Europe to enhance detection of non-clade B virus.
| Outcome | Efavirenz + ZDV + LAM (n=422) | Efavirenz + IDV (n=429) | IDV + ZDV + LAM (n=415) | |||
|---|---|---|---|---|---|---|
| Week 48 | Week 168 | Week 48 | Week 168 | Week 48 | Week 168 | |
| a Patients achieved and maintained confirmed HIV-1 RNA <400 copies/mL through Week 48 or Week 168. b Includes patients who rebounded, patients who were on study at Week 48 and failed to achieve confirmed HIV-1 RNA <400 copies/mL at time of discontinuation, and patients who discontinued due to lack of efficacy. c Includes consent withdrawn, lost to follow-up, noncompliance, never treated, missing data, protocol violation, death, and other reasons. Patients with HIV-1 RNA levels <400 copies/mL who chose not to continue in the voluntary extension phases of the study were censored at date of last dose of study medication. | ||||||
| Respondera | 69% | 48% | 57% | 40% | 50% | 29% |
| Virologic failureb | 6% | 12% | 15% | 20% | 13% | 19% |
| Discontinued for adverse events | 7% | 8% | 6% | 8% | 16% | 20% |
| Discontinued for other reasonsc | 17% | 31% | 22% | 32% | 21% | 32% |
| CD4+ cell count (cells/mm3) | | | | | | |
| Observed subjects (n) | (279) | (205) | (256) | (158) | (228) | (129) |
| Mean change from baseline | 190 | 329 | 191 | 319 | 180 | 329 |
For patients treated with efavirenz + zidovudine + lamivudine, efavirenz + indinavir, or indinavir + zidovudine + lamivudine, the percentage of responders with HIV-1 RNA <50 copies/mL was 65%, 50%, and 45%, respectively, through 48 weeks, and 43%, 31%, and 23%, respectively, through 168 weeks. A Kaplan-Meier analysis of time to loss of virologic response (HIV RNA <400 copies/mL) suggests that both the trends of virologic response and differences in response continue through 4 years.
ACTG 364 is a randomized, double-blind, placebo-controlled, 48-week study in NRTI-experienced patients who had completed two prior ACTG studies. One-hundred ninety-six patients (mean age 41 years [range 18 to 76], 74% Caucasian, 88% male) received NRTIs in combination with efavirenz (600 mg once daily), or nelfinavir (NFV, 750 mg three times daily), or efavirenz (600 mg once daily) + nelfinavir in a randomized, double-blinded manner. The mean baseline CD4+ cell count was 389 cells/mm3 and mean baseline HIV-1 RNA level was 8130 copies/mL. Upon entry into the study, all patients were assigned a new open-label NRTI regimen, which was dependent on their previous NRTI treatment experience. There was no significant difference in the mean CD4+ cell count among treatment groups; the overall mean increase was approximately 100 cells at 48 weeks among patients who continued on study regimens. Treatment outcomes are shown in Table 10. Plasma HIV RNA levels were quantified with the AMPLICOR HIV-1 MONITOR assay using a lower limit of quantification of 500 copies/mL.
| Outcome | Efavirenz + NFV + NRTIs (n=65) | Efavirenz + NRTIs (n=65) | NFV + NRTIs (n=66) |
|---|---|---|---|
| * For some patients, Week 56 data were used to confirm the status at Week 48. a Subjects achieved virologic response (two consecutive viral loads <500 copies/mL) and maintained it through Week 48. b Includes viral rebound and failure to achieve confirmed <500 copies/mL by Week 48. c See Adverse Reactions (6.1) for a safety profile of these regimens. d Includes loss to follow-up, consent withdrawn, noncompliance. | |||
| HIV-1 RNA <500 copies/mLa | 71% | 63% | 41% |
| HIV-1 RNA ≥500 copies/mLb | 17% | 34% | 54% |
| CDC Category C Event | 2% | 0% | 0% |
| Discontinuations for adverse eventsc | 3% | 3% | 5% |
| Discontinuations for other reasonsd | 8% | 0% | 0% |
A Kaplan-Meier analysis of time to treatment failure through 72 weeks demonstrates a longer duration of virologic suppression (HIV RNA <500 copies/mL) in the efavirenz-containing treatment arms.
Study AI266922 is an open-label study to evaluate the pharmacokinetics, safety, tolerability, and antiviral activity of efavirenz in combination with didanosine and emtricitabine in antiretroviral-naive and -experienced pediatric patients. Thirty-seven patients 3 months to 6 years of age (median 0.7 years) were treated with efavirenz. At baseline, median plasma HIV-1 RNA was 5.88 log10 copies/mL, median CD4+ cell count was 1144 cells/mm3, and median CD4+ percentage was 25%. The median time on study therapy was 60 weeks; 27% of patients discontinued before Week 48. Using an ITT analysis, the overall proportions of patients with HIV RNA <400 copies/mL and <50 copies/mL at Week 48 were 57% (21/37) and 46% (17/37), respectively. The median increase from baseline in CD4+ count at 48 weeks was 196 cells/mm3 and the median increase in CD4+ percentage was 6%.
Study PACTG 1021 was an open-label study to evaluate the pharmacokinetics, safety, tolerability, and antiviral activity of efavirenz in combination with didanosine and emtricitabine in pediatric patients who were antiretroviral therapy naive. Forty-three patients 3 months to 21 years of age (median 9.6 years) were dosed with efavirenz. At baseline, median plasma HIV-1 RNA was 4.8 log10 copies/mL, median CD4+ cell count was 367 cells/mm3, and median CD4+ percentage was 18%. The median time on study therapy was 181 weeks; 16% of patients discontinued before Week 48. Using an ITT analysis, the overall proportions of patients with HIV RNA <400 copies/mL and <50 copies/mL at Week 48 were 77% (33/43) and 70% (30/43), respectively. The median increase from baseline in CD4+ count at 48 weeks of therapy was 238 cells/mm3 and the median increase in CD4+ percentage was 13%.
Study PACTG 382 was an open-label study to evaluate the pharmacokinetics, safety, tolerability, and antiviral activity of efavirenz in combination with nelfinavir and an NRTI in antiretroviral-naive and NRTI-experienced pediatric patients. One hundred two patients 3 months to 16 years of age (median 5.7 years) were treated with efavirenz. Eighty-seven percent of patients had received prior antiretroviral therapy. At baseline, median plasma HIV-1 RNA was 4.57 log10 copies/mL, median CD4+ cell count was 755 cells/mm3, and median CD4+ percentage was 30%. The median time on study therapy was 118 weeks; 25% of patients discontinued before Week 48. Using an ITT analysis, the overall proportion of patients with HIV RNA <400 copies/mL and <50 copies/mL at Week 48 were 57% (58/102) and 43% (44/102), respectively. The median increase from baseline in CD4+ count at 48 weeks of therapy was 128 cells/mm3 and the median increase in CD4+ percentage was 5%.
Efavirenz tablets USP are available as follows:
Efavirenz tablets USP 600 mg are yellow colored oval biconvex film-coated tablets debossed ‘D’ on one side and ‘37’ on other side.
Bottles of 30 NDC 65862-049-30
30 Unit-dose Tablets NDC 65862-049-10
Efavirenz tablets should be stored at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature].
Advise the patient to read the FDA-approved patient labeling (Patient Information and Instructions for Use).
Drug Interactions
A statement to patients and healthcare providers is included on the product’s bottle labels:
ALERT: Find out about medicines that should NOT be taken with efavirenz tablets.
Efavirenz may interact with some drugs; therefore, advise patients to report to their doctor the use of any other prescription or nonprescription medication.
General Information for Patients
Inform patients that efavirenz is not a cure for HIV-1 infection and patients may continue to experience illnesses associated with HIV-1 infection, including opportunistic infections. Patients should remain under the care of a physician while taking efavirenz.
Advise patients to avoid doing things that can spread HIV-1 infection to others.
Dosing Instructions
Advise patients to take efavirenz every day as prescribed. If a patient forgets to take efavirenz, tell the patient to take the missed dose right away, unless it is almost time for the next dose. Advise the patient not to take 2 doses at one time and to take the next dose at the regularly scheduled time. Advise the patient to ask a healthcare provider if he/she needs help in planning the best times to take his/her medicine.
Efavirenz must always be used in combination with other antiretroviral drugs. Advise patients to take efavirenz on an empty stomach, preferably at bedtime. Taking efavirenz with food increases efavirenz concentrations and may increase the frequency of adverse reactions. Dosing at bedtime may improve the tolerability of nervous system symptoms [see Dosage and Administration (2) and Adverse Reactions (6.1)]. Healthcare providers should assist parents or caregivers in determining the best efavirenz dosing schedule for infants and young children.
For adult and pediatric patients who cannot swallow capsules or tablets, patients or their caregivers should be advised to read and carefully follow the instructions for administering the capsule contents in a small amount of food or infant formula [see Dosage and Administration (2.3) and FDA-approved patient labeling (Patient Information and Instructions for Use)]. Patients should call their healthcare provider or pharmacist if they have any questions.
Nervous System Symptoms
Inform patients that central nervous system symptoms (NSS) including dizziness, insomnia, impaired concentration, drowsiness, and abnormal dreams are commonly reported during the first weeks of therapy with efavirenz [see Warnings and Precautions (5.6)]. Dosing at bedtime may improve the tolerability of these symptoms, which are likely to improve with continued therapy. Alert patients to the potential for additive effects when efavirenz is used concomitantly with alcohol or psychoactive drugs. Instruct patients that if they experience NSS they should avoid potentially hazardous tasks such as driving or operating machinery.
Inform patients that there is a risk of developing late-onset neurotoxicity, including ataxia and encephalopathy which may occur months to years after beginning efavirenz therapy [see Warnings and Precautions (5.6)].
Psychiatric Symptoms
Inform patients that serious psychiatric symptoms including severe depression, suicide attempts, aggressive behavior, delusions, paranoia, psychosis-like symptoms and catatonia have been reported in patients receiving efavirenz [see Warnings and Precautions (5.5)]. If they experience severe psychiatric adverse experiences they should seek immediate medical evaluation. Advise patients to inform their physician of any history of mental illness or substance abuse.
Rash
Inform patients that a common side effect is rash [see Warnings and Precautions (5.8)]. Rashes usually go away without any change in treatment. However, since rash may be serious, advise patients to contact their physician promptly if rash occurs.
Hepatotoxicity
Inform patients to watch for early warning signs of liver inflammation or failure, such as fatigue, weakness, lack of appetite, nausea and vomiting, as well as later signs such as jaundice, confusion, abdominal swelling, and discolored feces, and to consult their health care professional without delay if such symptoms occur [see Warnings and Precautions (5.9) and Adverse Reactions (6.1)].
Females of Reproductive Potential
Advise females of reproductive potential to use effective contraception as well as a barrier method during treatment with efavirenz and for 12 weeks after discontinuing efavirenz. Advise patients to contact their healthcare provider if they plan to become pregnant, become pregnant, or if pregnancy is suspected during treatment with efavirenz [see Warnings and Precautions (5.7) and Use in Specific Populations (8.1, 8.3)].
Pregnancy Exposure Registry
Advise patients that there is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to efavirenz during pregnancy [see Use in Specific Populations (8.1)].
Fat Redistribution
Inform patients that redistribution or accumulation of body fat may occur in patients receiving antiretroviral therapy and that the cause and long-term health effects of these conditions are not known [see Warnings and Precautions (5.13)].
Efavirenz Tablets USP
(eh-FAV-ir-enz)
Important: Ask your doctor or pharmacist about medicines that should not be taken with efavirenz tablets. For more information, see the section “What should I tell my doctor before taking efavirenz tablets?”
Read this Patient Information before you start taking efavirenz tablets and each time you get a refill. There may be new information. This information does not take the place of talking with your doctor about your medical condition or treatment.
What are efavirenz tablets?
Efavirenz tablets are a prescription HIV-1 (Human Immunodeficiency Virus type 1) medicine used with other antiretroviral medicines to treat HIV-1 infection in adults and in children who are at least 3 months old and who weigh at least 7 pounds 12 ounces (3.5 kg). HIV is the virus that causes AIDS (Acquired Immune Deficiency Syndrome).
It is not known if efavirenz tablets are safe and effective in children younger than 3 months of age or who weigh less than 7 pounds 12 ounces (3.5 kg).
When used with other antiretroviral medicines to treat HIV-1 infection, efavirenz tablets may help:
Reducing the amount of HIV-1 and increasing the CD4+ (T) cells in your blood may help improve your immune system. This may reduce your risk of death or getting infections that can happen when your immune system is weak (opportunistic infections).
Efavirenz tablets do not cure HIV-1 infection or AIDS. You should keep taking HIV-1 medicines to control HIV-1 infection and decrease HIV-related illnesses.
Avoid doing things that can spread HIV-1 infection to others:
Ask your doctor if you have any questions about how to prevent passing HIV to other people.
Who should not take efavirenz tablets?
Do not take efavirenz tablets if you are allergic to efavirenz or any of the ingredients in efavirenz tablets. See the end of this leaflet for a complete list of ingredients in efavirenz tablets.
Do not take efavirenz tablets if you are currently taking elbasvir and grazoprevir (ZEPATIER®).
What should I tell my doctor before taking efavirenz tablets?
Before taking efavirenz tablets, tell your doctor if you have any medical conditions and in particular, if you:
Females who are able to become pregnant should use 2 effective forms of birth control during treatment and for 12 weeks after stopping treatment with efavirenz tablets. A barrier form of birth control should always be used along with another type of birth control.
Tell your doctor and pharmacist about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
Efavirenz tablets may affect the way other medicines work, and other medicines may affect how efavirenz tablets work, and may cause serious side effects. If you take certain medicines with efavirenz tablets, the amount of efavirenz in your body may be too low and it may not work to help control your HIV infection. The HIV virus in your body may become resistant to efavirenz or other HIV medicines that are like it.
You should not take efavirenz tablets if you take ATRIPLA (efavirenz, emtricitabine, tenofovir disoproxil fumarate) unless your doctor tells you to.
Tell your doctor and pharmacist about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Some medicines interact with efavirenz tablets.
Keep a list of your medicines to show your doctor and pharmacist.
How should I take efavirenz tablets?
How and when to take efavirenz tablets.
What are the possible side effects of efavirenz tablets?
Efavirenz tablets may cause serious side effects, including:
If you have dizziness, trouble concentrating or drowsiness, do not drive a car, use machinery, or do anything that needs you to be alert.
Some nervous system symptoms (e.g., confusion, slow thoughts and physical movement, and delusions [false beliefs] or hallucinations [seeing or hearing things that others do not see or hear]) may occur months to years after beginning efavirenz tablets therapy. Promptly contact your health care provider should any of these symptoms occur.
The most common side effects of efavirenz tablets include:
Some patients taking efavirenz tablets have experienced increased levels of lipids (cholesterol and triglycerides) in the blood. Tell your doctor if you have any side effect that bothers you or that does not go away.
These are not all the possible side effects of efavirenz tablets. For more information, ask your doctor or pharmacist.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
How should I store efavirenz tablets?
Keep efavirenz tablets and all medicines out of the reach of children.
General information about efavirenz tablets
Medicines are sometimes prescribed for purposes other than those listed in a Patient Information leaflet. Do not use efavirenz tablets for a condition for which it was not prescribed. Do not give efavirenz tablets to other people, even if they have the same symptoms that you have. They may harm them.
If you would like more information, talk with your doctor. You can ask your pharmacist or doctor for information about efavirenz tablets that is written for health professionals. For more information, call Aurobindo Pharma USA, Inc. at 1-866-850-2876.
What are the ingredients in efavirenz tablets?
Active ingredient: efavirenz
Inactive ingredients:
Efavirenz tablets: croscarmellose sodium, hydroxypropyl cellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium lauryl sulfate. The film coating contains hypromellose, polyethylene glycol, titanium dioxide, and yellow iron oxide.
This Patient Information has been approved by the U.S. Food and Drug Administration.
Distributed by:
Aurobindo Pharma USA, Inc.
279 Princeton-Hightstown Road
East Windsor, NJ 08520
Manufactured by:
Aurobindo Pharma Limited
Hyderabad-500 038, India
Revised: 12/2019
ATRIPLA is a registered trademark of Bristol-Myers Squibb & Gilead Sciences, LLC. Other brands listed are the trademarks of their respective owners and are not trademarks of Aurobindo Pharma Limited. The owners of these brands are not affiliated with and do not endorse Aurobindo Pharma Limited or its products.
NDC 65862-049-30
Rx only
Efavirenz Tablets USP
600 mg
ALERT: Find out about medicines that should
NOT be taken with Efavirenz Tablets.
AUROBINDO 30 Tablets
Package Label (PRINCIPAL DISPLAY PANEL – 600 mg (30 Tablet Bottle))
NDC 65862-049-10
Rx only
Efavirenz Tablets USP
600 mg
ALERT: Find out about medicines that should NOT be taken with Efavirenz
Tablets.
AUROBINDO 30 Tablets (3 x 10 Unit-dose)
Package Label-principal Display Panel (600 mg Blister Carton (3 x 10 Unit-dose))
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