Other
SUICIDALITY AND ANTIDEPRESSANT DRUGS
Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term trials. These trials did not show an increase in the risk of suicidal thoughts and behavior with antidepressant use in subjects aged 65 and older [see Warnings and Precautions (5.1)].
In patients of all ages who are started on antidepressant therapy, monitor closely for worsening, and for emergence of suicidal thoughts and behaviors. Advise families and caregivers of the need for close observation and communication with the prescriber [see Warnings and Precautions (5.1)].
Incidence of Seizure with Bupropion Use
The incidence of seizure with bupropion hydrochloride extended-release tablets (XL) has not been formally evaluated in clinical trials. In studies using bupropion HCl sustained-release up to 300 mg per day the incidence of seizure was approximately 0.1% (1/1,000 patients). In a large prospective, follow-up study, the seizure incidence was approximately 0.4% (13/3,200) with bupropion HCl immediate-release in the range of 300 mg to 450 mg per day.
Additional data accumulated for bupropion immediate-release suggests that the estimated seizure incidence increases almost tenfold between 450 and 600 mg/day. The risk of seizure can be reduced if the bupropion hydrochloride extended-release tablets (XL) dose does not exceed 450 mg once daily and the titration rate is gradual.
Commonly Observed Adverse Reactions in Controlled Clinical Trials of Sustained-Release Bupropion Hydrochloride
Adverse reactions that occurred in at least 5% of patients treated with bupropion HCl sustained-release (300 mg and 400 mg per day) and at a rate at least twice the placebo rate are listed below.
300 mg/day of bupropion HCl sustained-release: anorexia, dry mouth, rash, sweating, tinnitus, and tremor.
400 mg/day of bupropion HCl sustained-release: abdominal pain, agitation, anxiety, dizziness, dry mouth, insomnia, myalgia, nausea, palpitation, pharyngitis, sweating, tinnitus, and urinary frequency.
Bupropion hydrochloride extended-release tablets (XL) has been demonstrated to have similar bioavailability both to the immediate-release and sustained-release formulations of bupropion. The information included under this subsection and under subsection 6.2 is based primarily on data from controlled clinical trials with the sustained-release and extended-release formulations of bupropion hydrochloride.
Major Depressive Disorder
Adverse Reactions Leading to Discontinuation of Treatment with Bupropion HCl Immediate-Release, Bupropion HCl Sustained-Release, and Bupropion HCl Extended-Release in Major Depressive Disorder Trials
In placebo-controlled clinical trials with bupropion HCl sustained-release, 4%, 9%, and 11% of the placebo, 300 mg/day and 400 mg/day groups, respectively, discontinued treatment because of adverse reactions. The specific adverse reactions leading to discontinuation in at least 1% of the 300 mg/day or 400 mg/day groups and at a rate at least twice the placebo rate are listed in Table 2.
| Adverse Reaction Term | Placebo (n=385) | Bupropion HCl Sustained-Release 300 mg/day (n=376) | Bupropion HCl Sustained-Release 400 mg/day (n=114) |
|---|---|---|---|
| Rash | 0.0% | 2.4% | 0.9% |
| Nausea | 0.3% | 0.8% | 1.8% |
| Agitation | 0.3% | 0.3% | 1.8% |
| Migraine | 0.3% | 0.0% | 1.8% |
In clinical trials with bupropion HCl immediate-release, 10% of patients and volunteers discontinued due to an adverse reaction. Reactions resulting in discontinuation (in addition to those listed above for the sustained-release formulation) included vomiting, seizures, and sleep disturbances.
Adverse Reactions Occurring at an Incidence of >1% in Patients Treated with Bupropion HCl Immediate-Release or Bupropion HCl Sustained-Release in MDD
Table 3 summarizes the adverse reactions that occurred in placebo-controlled trials in patients treated with bupropion HCl sustained-release 300 mg/day and 400 mg/day. These include reactions that occurred in either the 300 mg or 400 mg group at an incidence of 1% or more and were more frequent than in the placebo group.
| Body System/ Adverse Reaction | Placebo (n=385) | Bupropion HCl Sustained-Release 300 mg/day (n=376) | Bupropion HCl Sustained-Release 400 mg/day (n=114) |
|---|---|---|---|
| Body (General) | |||
| Headache | 23% | 26% | 25% |
| Infection | 6% | 8% | 9% |
| Abdominal pain | 2% | 3% | 9% |
| Asthenia | 2% | 2% | 4% |
| Chest pain | 1% | 3% | 4% |
| Pain | 2% | 2% | 3% |
| Fever | - | 1% | 2% |
| Cardiovascular | |||
| Palpitation | 2% | 2% | 6% |
| Flushing | - | 1% | 4% |
| Migraine | 1% | 1% | 4% |
| Hot flashes | 1% | 1% | 3% |
| Digestive | |||
| Dry mouth | 7% | 17% | 24% |
| Nausea | 8% | 13% | 18% |
| Constipation | 7% | 10% | 5% |
| Diarrhea | 6% | 5% | 7% |
| Anorexia | 2% | 5% | 3% |
| Vomiting | 2% | 4% | 2% |
| Dysphagia | 0% | 0% | 2% |
| Musculoskeletal | |||
| Myalgia | 3% | 2% | 6% |
| Arthralgia | 1% | 1% | 4% |
| Arthritis | 0% | 0% | 2% |
| Twitch | - | 1% | 2% |
| Nervous System | |||
| Insomnia | 6% | 11% | 16% |
| Dizziness | 5% | 7% | 11% |
| Agitation | 2% | 3% | 9% |
| Anxiety | 3% | 5% | 6% |
| Tremor | 1% | 6% | 3% |
| Nervousness | 3% | 5% | 3% |
| Somnolence | 2% | 2% | 3% |
| Irritability | 2% | 3% | 2% |
| Memory decreased | 1% | - | 3% |
| Paresthesia | 1% | 1% | 2% |
| Central nervous system stimulation | 1% | 2% | 1% |
| Respiratory | |||
| Pharyngitis | 2% | 3% | 11% |
| Sinusitis | 2% | 3% | 1% |
| Increased cough | 1% | 1% | 2% |
| Skin | |||
| Sweating | 2% | 6% | 5% |
| Rash | 1% | 5% | 4% |
| Pruritus | 2% | 2% | 4% |
| Urticaria | 0% | 2% | 1% |
| Special Senses | |||
| Tinnitus | 2% | 6% | 6% |
| Taste perversion | - | 2% | 4% |
| Blurred vision or diplopia | 2% | 3% | 2% |
| Urogenital | |||
| Urinary frequency | 2% | 2% | 5% |
| Urinary urgency | 0% | - | 2% |
| Vaginal hemorrhage Incidence based on the number of female patients. | - | 0% | 2% |
| Urinary tract infection | - Hyphen denotes adverse reactions occurring in greater than 0 but less than 0.5% of patients | 1% | 0% |
The following additional adverse reactions occurred in controlled trials of bupropion HCl immediate-release (300 to 600 mg per day) at an incidence of at least 1% more frequently than in the placebo group were: cardiac arrhythmia (5% vs. 4%), hypertension (4% vs. 2%), hypotension (3% vs. 2%), menstrual complaints (5% vs. 1%), akathisia (2% vs. 1%), impaired sleep quality (4% vs. 2%), sensory disturbance (4% vs. 3%), confusion (8% vs. 5%), decreased libido (3% vs. 2%), hostility (6% vs. 4%), auditory disturbance (5% vs. 3%), and gustatory disturbance (3% vs. 1%).
Seasonal Affective Disorder
In placebo-controlled clinical trials in SAD, 9% of patients treated with bupropion hydrochloride extended-release tablets (XL) and 5% of patients treated with placebo discontinued treatment because of adverse reactions. The adverse reactions leading to discontinuation in at least 1% of patients treated with bupropion and at a rate numerically greater than the placebo rate were insomnia (2% vs. <1%) and headache (1% vs. <1%).
Table 4 summarizes the adverse reactions that occurred in patients treated with bupropion hydrochloride extended-release tablets (XL) for up to approximately 6 months in 3 placebo controlled trials. These include reactions that occurred at an incidence of 2% or more and were more frequent than in the placebo group.
| System Organ Class/Preferred Team | Placebo (n=511) | Bupropion HCL Extended-Release (n=537) |
|---|---|---|
| Gastrointestinal Disorder | ||
| Dry mouth | 15% | 26% |
| Nausea | 8% | 13% |
| Constipation | 2% | 9% |
| Flatulence | 3% | 6% |
| Abdominal pain | <1% | 2% |
| Nervous System Disorders | ||
| Headache | 26% | 34% |
| Dizziness | 5% | 6% |
| Tremor | <1% | 3% |
| Infections and Infestations | ||
| Nasopharyngitis | 12% | 13% |
| Upper respiratory tract infection | 8% | 9% |
| Sinusitis | 4% | 5% |
| Psychiatric Disorders | ||
| Insomnia | 13% | 20% |
| Anxiety | 5% | 7% |
| Abnormal Dreams | 2% | 3% |
| Agitation | <1% | 2% |
| Musculoskeletal and Connective Tissue Disorders | ||
| Myalgia | 2% | 3% |
| Pain extremity | 2% | 3% |
| Respiratory, Thoracic, and Mediastinal Disorders | ||
| Cough | 3% | 4% |
| General Disorders and Administration Site Conditions | ||
| Feeling jittery | 2% | 3% |
| Skin and Subcutaneous Tissue Disorders | ||
| Rash | 2% | 3% |
| Metabolism and Nutrition Disorders | ||
| Decreased appetite | 1% | 4% |
| Reproductive System and Breast Disorders | ||
| Dysmenorrhea | <1% | 2% |
| Ear and Labyrinth Disorders | ||
| Tinnitus | <1% | 3% |
| Vascular Disorders | ||
| Hypertension | 0% | 2% |
Changes in Body Weight
Table 5 presents the incidence of body weight changes (≥5 lbs) in the short-term MDD trials using bupropion HCl sustained-release. There was a dose-related decrease in body weight.
| Weight Change | Bupropion HCL Sustained-Release 300 mg/day (n=339) | Bupropion HCL Sustained-Release 400 mg/day (n=112) | Placebo (n=347) |
|---|---|---|---|
| Gained > 5 lbs | 3% | 2% | 4% |
| Lost > 5 lbs | 14% | 19% | 6% |
Table 6 presents the incidence of body weight changes (≥5 lbs) in the 3 SAD trials using bupropion HCl extended-release. A higher proportion of subjects in the bupropion group (23%) had a weight loss ≥5 lbs, compared to the placebo group (11%). These were relatively long-term trials (up to 6 months).
| Weight Change | Bupropion HCL Extended-Release 150 to 300 mg/day (n=539) | Placebo (n=511) |
|---|---|---|
| Gained > 5 lbs | 11% | 21% |
| Lost > 5 lbs | 23% | 11% |
Body (General)
Chills, facial edema, edema, peripheral edema, musculoskeletal chest pain, photosensitivity, and malaise.
Cardiovascular
Postural hypotension, hypertension, stroke, vasodilation, syncope, complete atrioventricular block, extrasystoles, myocardial infarction, phlebitis, pulmonary embolism, and Brugada pattern/syndrome.
Digestive
Abnormal liver function, bruxism, gastric reflux, gingivitis, glossitis, increased salivation, jaundice, mouth ulcers, stomatitis, thirst, edema of tongue, colitis, esophagitis, gastrointestinal hemorrhage, gum hemorrhage, hepatitis, intestinal perforation, liver damage, pancreatitis, and stomach ulcer.
Endocrine
Hyperglycemia, hypoglycemia, and syndrome of inappropriate antidiuretic hormone secretion.
Hemic and Lymphatic
Ecchymosis, anemia, leukocytosis, leukopenia, lymphadenopathy, pancytopenia, and thrombocytopenia. Altered PT and/or INR, associated with hemorrhagic or thrombotic complications, were observed when bupropion was coadministered with warfarin.
Metabolic and Nutritional
Glycosuria.
Musculoskeletal
Leg cramps, fever/rhabdomyolysis, and muscle weakness.
Nervous System
Abnormal coordination, depersonalization, emotional lability, hyperkinesia, hypertonia, hypesthesia, vertigo, amnesia, ataxia, derealization, abnormal electroencephalogram (EEG), aggression, akinesia, aphasia, coma, dysarthria, dyskinesia, dystonia, euphoria, extrapyramidal syndrome, hypokinesia, increased libido, neuralgia, neuropathy, paranoid ideation, restlessness, suicide attempt, and unmasking tardive dyskinesia.
Respiratory
Bronchospasm and pneumonia.
Skin and Subcutaneous Tissue Disorders
Maculopapular rash, alopecia, angioedema, exfoliative dermatitis, hirsutism, acute generalized exanthematous pustulosis, and drug reaction with eosinophilias and system symptoms (DRESS).
Special Senses
Accommodation abnormality, dry eye, deafness, increased intraocular pressure, angle-closure glaucoma, and mydriasis.
Urogenital
Impotence, polyuria, prostate disorder, abnormal ejaculation, cystitis, dyspareunia, dysuria, gynecomastia, menopause, painful erection, salpingitis, urinary incontinence, urinary retention, and vaginitis.
Inhibitors of CYP2B6
Ticlopidine and Clopidogrel: Concomitant treatment with these drugs can increase bupropion exposures but decrease hydroxybupropion exposure. Based on clinical response, dosage adjustment of bupropion hydrochloride may be necessary when coadministered with CYP2B6 inhibitors (e.g., ticlopidine or clopidogrel) [see Clinical Pharmacology (12.3)].
Inducers of CYP2B6
Ritonavir, Lopinavir, and Efavirenz: Concomitant treatment with these drugs can decrease bupropion and hydroxybupropion exposure. Dosage increase of bupropion hydrochloride may be necessary when coadministered with ritonavir, lopinavir, or efavirenz but should not exceed the maximum recommended dose [see Clinical Pharmacology (12.3)].
Carbamazepine, Phenobarbital, Phenytoin: While not systemically studied, these drugs may induce metabolism of bupropion and may decrease bupropion exposure [see Clinical Pharmacology (12.3)]. If bupropion is used concomitantly with a CYP inducer, it may be necessary to increase the dose of bupropion, but the maximum recommended dose should not be exceeded.
Drugs Metabolized by CYP2D6
Bupropion and its metabolites (erythrohydrobupropion, threohydrobupropion, hydroxybupropion) are CYP2D6 inhibitors. Therefore, coadministration of bupropion hydrochloride with drugs that are metabolized by CYP2D6 can increase the exposures of drugs that are substrates of CYP2D6. Such drugs include certain antidepressants (e.g., venlafaxine, nortriptyline, imipramine, desipramine, paroxetine, fluoxetine, and sertraline), antipsychotics (e.g., haloperidol, risperidone, and thioridazine), beta-blockers (e.g., metoprolol), and Type 1C antiarrhythmics (e.g., propafenone, and flecainide). When used concomitantly with bupropion hydrochloride, it may be necessary to decrease the dose of these CYP2D6 substrates, particularly for drugs with a narrow therapeutic index.
Drugs that require metabolic activation by CYP2D6 to be effective (e.g., tamoxifen), theoretically could have reduced efficacy when administered concomitantly with inhibitors of CYP2D6 such as bupropion. Patients treated concomitantly with bupropion hydrochloride and such drugs may require increased doses of the drug [see Clinical Pharmacology (12.3)].
Pregnancy Exposure Registry
There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antidepressants during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for Antidepressants at 1-844-405-6185 or visiting online at https://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/antidepressants/.
Risk Summary
Data from epidemiological studies of pregnant women exposed to bupropion in the first trimester have not identified an increased risk of congenital malformations overall (see Data). There are risks to the mother associated with untreated depression (see Clinical Considerations). When bupropion was administered to pregnant rats during organogenesis, there was no evidence of fetal malformations at doses up to approximately 10 times the maximum recommended human dose (MRHD) of 450 mg/day. When given to pregnant rabbits during organogenesis, non-dose-related increases in incidence of fetal malformations and skeletal variations were observed at doses approximately equal to the MRHD and greater. Decreased fetal weights were seen at doses twice the MRHD and greater (see Animal Data).
The estimated background risk for major birth defects and miscarriage are unknown for the indicated population. All pregnancies have a background rate of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Clinical Considerations
Disease-Associated Maternal and/or Embryo/Fetal Risk
A prospective, longitudinal study followed 201 pregnant women with a history of major depressive disorder who were euthymic and taking antidepressants during pregnancy at the beginning of pregnancy. The women who discontinued antidepressants during pregnancy were more likely to experience a relapse of major depression than women who continued antidepressants. Consider the risks to the mother of untreated depression and potential effects on the fetus when discontinuing or changing treatment with antidepressant medications during pregnancy and postpartum.
Data
Human Data
Data from the international bupropion Pregnancy Registry (675 first trimester exposures) and a retrospective cohort study using the United Healthcare database (1,213 first trimester exposures) did not show an increased risk for malformations overall. The Registry was not designed or powered to evaluate specific defects but suggested a possible increase in cardiac malformations.
No increased risk for cardiovascular malformations overall has been observed after bupropion exposure during the first trimester. The prospectively observed rate of cardiovascular malformations in pregnancies with exposure to bupropion in the first trimester from the international Pregnancy Registry was 1.3% (9 cardiovascular malformations/675 first-trimester maternal bupropion exposures), which is similar to the background rate of cardiovascular malformations (approximately 1%). Data from the United Healthcare database, which has a limited number of exposed cases with cardiovascular malformations, and a case-controlled study (6,853 infants with cardiovascular malformations and 5,753 with non-cardiovascular malformations) from the National Birth Defects Prevention Study (NBDPS) did not show an increased risk for cardiovascular malformations overall after bupropion exposure during the first trimester.
Study findings on bupropion exposure during the first trimester and risk left ventricular outflow tract obstruction (LVOTO) are inconsistent and do not allow conclusions regarding possible association. The United Healthcare database lacked sufficient power to evaluate this association; the NBDPS found increased risk for LVOTO (n = 10; adjusted odds ratio (OR) = 2.6; 95% CI 1.2, 5.7), and the Slone Epidemiology case control study did not find increased risk for LVOTO.
Study findings on bupropion exposure during the first trimester and risk for ventricular septal defect (VSD) are inconsistent and do not allow conclusions regarding a possible association. The Slone Epidemiology Study found an increased risk for VSD following first trimester maternal bupropion exposure (n = 17; adjusted OR = 2.5; 95% CI: 1.3, 5.0) but did not find an increased risk for any other cardiovascular malformations studied (including LVOTO as above). The NBDPS and United Healthcare database study did not find an association between first trimester maternal bupropion exposure and VSD.
For the findings of LVOTO and VSD, the studies were limited by the small number of exposed cases, inconsistent findings among studies, and the potential for chance findings from multiple comparisons in case control studies.
Animal Data
In studies conducted in pregnant rats and rabbits, bupropion was administered orally during the period of organogenesis at doses of up to 450 and 150 mg/kg/day, respectively (approximately 10 and 6 times the MRHD, respectively, on a mg/m2 basis). There was no evidence of fetal malformations in rats. When given to pregnant rabbits during organogenesis, non-dose-related increases in incidence of fetal malformations and skeletal variations were observed at the lowest dose tested (25 mg/kg/day, approximately equal to the MRHD on a mg/m2 basis) and greater. Decreased fetal weights were observed at doses of 50 mg/kg/day (approximately 2 times the MRHD on a mg/m2 basis) and greater. No maternal toxicity was evident at doses of 50 mg/kg/day or less.
In a pre- and postnatal development study, bupropion administered orally to pregnant rats at doses of up to 150 mg/kg/day (approximately 3 times the MRHD on a mg/m2 basis) from embryonic implantation through lactation had no effect on pup growth or development.
Risk Summary
Data from published literature report the presence of bupropion and its metabolites in human milk (see Data). There are no data on the effects of bupropion or its metabolites on milk production. Limited data from postmarketing reports have not identified a clear association of adverse reactions in the breastfed infant. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for bupropion hydrochloride and any potential adverse effects on the breastfed child from bupropion hydrochloride or from the underlying maternal condition.
Data
In a lactation study of ten women, levels of orally dosed bupropion and its active metabolites were measured in expressed milk. The average daily infant exposure (assuming 150 mL/kg daily consumption) to bupropion and its active metabolites was 2% of the maternal weight-adjusted dose. Postmarketing reports have described seizures in breastfed infants. The relationship of bupropion exposure and these seizures is unclear.
Humans
Controlled clinical studies of bupropion HCl immediate-release conducted in normal volunteers, in subjects with a history of multiple drug abuse, and in depressed patients demonstrated an increase in motor activity and agitation/excitement.
In a population of individuals experienced with drugs of abuse, a single dose of 400 mg bupropion produced mild amphetamine-like activity as compared to placebo on the Morphine-Benzedrine Subscale of the Addiction Research Center Inventories (ARCI), and a score intermediate between placebo and amphetamine on the Liking Scale of the ARCI. These scales measure general feelings of euphoria and drug desirability.
Findings in clinical trials, however, are not known to reliably predict the abuse potential of drugs. Nonetheless, evidence from single-dose studies does suggest that the recommended daily dosage of bupropion when administered in divided doses is not likely to be significantly reinforcing to amphetamine or CNS stimulant abusers. However, higher doses (that could not be tested because of the risk of seizure) might be modestly attractive to those who abuse CNS stimulant drugs.
Bupropion hydrochloride extended-release tablets are intended for oral use only. The inhalation of crushed tablets or injection of dissolved bupropion has been reported. Seizures and/or cases of death have been reported when bupropion has been administered intranasally or by parenteral injection.
Animals
Studies in rodents and primates demonstrated that bupropion exhibits some pharmacologic actions common to psychostimulants. In rodents, it has been shown to increase locomotor activity, elicit a mild stereotyped behavioral response, and increase rates of responding in several schedule-controlled behavior paradigms. In primate models assessing the positive reinforcing effects of psychoactive drugs, bupropion was self-administered intravenously. In rats, bupropion produced amphetamine-like and cocaine-like discriminative stimulus effects in drug discrimination paradigms used to characterize the subjective effects of psychoactive drugs.
Absorption
Following single oral administration of bupropion hydrochloride extended-release tablets (XL) to healthy volunteers, the median time to peak plasma concentrations for bupropion was approximately 5 hours. The presence of food did not affect the peak concentration or area under the curve of bupropion.
Distribution
In vitro tests show that bupropion is 84% bound to human plasma proteins at concentrations up to 200 mcg/mL. The extent of protein binding of the hydroxybupropion metabolite is similar to that for bupropion, whereas the extent of protein binding of the threohydrobupropion metabolite is about half that of bupropion.
Metabolism
Bupropion is extensively metabolized in humans. Three metabolites are active: hydroxybupropion, which is formed via hydroxylation of the tert-butyl group of bupropion, and the amino-alcohol isomers threohydrobupropion and erythrohydrobupropion, which are formed via reduction of the carbonyl group. In vitro findings suggest that CYP2B6 is the principal isoenzyme involved in the formation of hydroxybupropion, while cytochrome P450 enzymes are not involved in the formation of threohydrobupropion. Oxidation of the bupropion side chain results in the formation of a glycine conjugate of meta-chlorobenzoic acid, which is then excreted as the major urinary metabolite. The potency and toxicity of the metabolites relative to bupropion have not been fully characterized. However, it has been demonstrated in an antidepressant screening test in mice that hydroxybupropion is one half as potent as bupropion, while threohydrobupropion and erythrohydrobupropion are 5-fold less potent than bupropion. This may be of clinical importance, because the plasma concentrations of the metabolites are as high or higher than those of bupropion.
At steady state, peak plasma concentration of hydroxybupropion occurred approximately 7 hours after administration of bupropion hydrochloride extended-release tablets (XL), and it was approximately 7 times the peak level of the parent drug. The elimination half-life of hydroxybupropion is approximately 20 (±5) hours, and its AUC at steady state is about 13 times that of bupropion. The times to peak concentrations for the erythrohydrobupropion and threohydrobupropion metabolites are similar to that of hydroxybupropion. However, the elimination half-lives of erythrohydrobupropion and threohydrobupropion are longer, approximately 33 (±10) and 37 (±13) hours, respectively, and steady state AUCs were 1.4 and 7 times that of bupropion, respectively.
Bupropion and its metabolites exhibit linear kinetics following chronic administration of 300 to 450 mg/day.
Elimination
Following oral administration of 200 mg of C-bupropion in humans, 87% and 10% of the radioactive 14 dose were recovered in the urine and feces, respectively. Only 0.5% of the oral dose was excreted as unchanged bupropion.
Population Subgroups
Factors or conditions altering metabolic capacity (e.g., liver disease, congestive heart failure [CHF], age, concomitant medications, etc.) or elimination may be expected to influence the degree and extent of accumulation of the active metabolites of bupropion. The elimination of the major metabolites of bupropion may be affected by reduced renal or hepatic function, because they are moderately polar compounds and are likely to undergo further metabolism or conjugation in the liver prior to urinary excretion.
Renal Impairment
There is limited information on the pharmacokinetics of bupropion in patients with renal impairment. An inter-trial comparison between normal subjects and subjects with end-stage renal failure demonstrated that the parent drug Cmax and AUC values were comparable in the 2 groups, whereas the hydroxybupropion and threohydrobupropion metabolites had a 2.3- and 2.8-fold increase, respectively, in AUC for subjects with end-stage renal failure. A second study, comparing normal subjects and subjects with moderate-to-severe renal impairment (GFR 30.9 ± 10.8 mL/min) showed that after a single 150 mg dose of sustained-release bupropion, exposure to bupropion was approximately 2-fold higher in subjects with impaired renal function, while levels of the hydroxybupropion and threo/erythrohydrobupropion (combined) metabolites were similar in the 2 groups. Bupropion is extensively metabolized in the liver to active metabolites, which are further metabolized and subsequently excreted by the kidneys. The elimination of the major metabolites of bupropion may be reduced by impaired renal function. Bupropion hydrochloride should be used with caution in patients with renal impairment, and a reduced frequency and/or dose should be considered [see Dosage and Administration (2.7), Use in Specific Populations (8.6)].
Hepatic Impairment
The effect of hepatic impairment on the pharmacokinetics of bupropion was characterized in 2 single dose trials, one in subjects with alcoholic liver disease and one in subjects with mild to severe cirrhosis. The first trial demonstrated that the half-life of hydroxybupropion was significantly longer in 8 subjects with alcoholic liver disease than in 8 healthy volunteers (32±14 hours versus 21±5 hours, respectively). Although not statistically significant, the AUCs for bupropion and hydroxybupropion were more variable and tended to be greater (by 53% to 57%) in patients with alcoholic liver disease. The differences in half life for bupropion and the other metabolites in the 2 groups were minimal.
The second trial demonstrated no statistically significant differences in the pharmacokinetics of bupropion and its active metabolites in 9 subjects with mild to moderate hepatic cirrhosis compared to 8 healthy volunteers. However, more variability was observed in some of the pharmacokinetic parameters for bupropion (AUC, Cmax , and Tmax ) and its active metabolites (t1/2 ) in subjects with mild to moderate hepatic cirrhosis. In addition, in patients with severe hepatic cirrhosis, the bupropion Cmax and AUC were substantially increased (mean difference: by approximately 70% and 3-fold, respectively) and more variable when compared to values in healthy volunteers; the mean bupropion half-life was also longer (29 hours in subjects with severe hepatic cirrhosis vs. 19 hours in healthy subjects). For the metabolite hydroxybupropion, the mean Cmax was approximately 69% lower. For the combined amino-alcohol isomers threohydrobupropion and erythrohydrobupropion, the mean Cmax was approximately 31% lower. The mean AUC increased by about 1½-fold for hydroxybupropion and about 2½-fold for threo/erythrohydrobupropion. The median Tmax was observed 19 hours later for hydroxybupropion and 31 hours later for threo/erythrohydrobupropion. The mean half-lives for hydroxybupropion and threo/erythrohydrobupropion were increased 5- and 2-fold, respectively, in patients with severe hepatic cirrhosis compared to healthy volunteers [see Dosage and Administration (2.6), Use in Specific Populations (8.7)].
Left Ventricular Dysfunction
During a chronic dosing study with bupropion in 14 depressed patients with left ventricular dysfunction (history of CHF or an enlarged heart on x-ray), there was no apparent effect on the pharmacokinetics of bupropion or its metabolites, compared to healthy volunteers.
Age
The effects of age on the pharmacokinetics of bupropion and its metabolites have not been fully characterized, but an exploration of steady-state bupropion concentrations from several depression efficacy studies involving patients dosed in a range of 300 to 750 mg/day, on a 3 times daily schedule, revealed no relationship between age (18 to 83 years) and plasma concentration of bupropion. A single-dose pharmacokinetic study demonstrated that the disposition of bupropion and its metabolites in elderly subjects was similar to that in younger subjects. These data suggest that there is no prominent effect of age on bupropion concentration; however, another single- and multiple-dose pharmacokinetic study suggested that the elderly are at increased risk for accumulation of bupropion and its metabolites [see Use in Specific Populations (8.5)].
Gender
A single-dose study involving 12 healthy male and 12 healthy female volunteers revealed no sex-related differences in the pharmacokinetic parameters of bupropion. In addition, pooled analysis of bupropion pharmacokinetic data from 90 healthy male and 90 healthy female volunteers revealed no sex-related differences in the peak plasma concentrations of bupropion. The mean systemic exposure (AUC) was approximately 13% higher in male volunteers compared to female volunteers.
Smokers
The effects of cigarette smoking on the pharmacokinetics of bupropion hydrochloride were studied in 34 healthy male and female volunteers; 17 were chronic cigarette smokers and 17 were nonsmokers. Following oral administration of a single 150 mg dose of bupropion, there was no statistically significant difference in Cmax , half-life, Tmax , AUC, or clearance of bupropion or its active metabolites between smokers and nonsmokers.
Drug Interactions
Potential for Other Drugs to Affect Bupropion Hydrochloride
In vitro studies indicate that bupropion is primarily metabolized to hydroxybupropion by CYP2B6. Therefore, the potential exists for drug interactions between bupropion hydrochloride and drugs that are inhibitors or inducers of CYP2B6. In addition, in vitro studies suggest that paroxetine, sertraline, norfluoxetine, fluvoxamine, and nelfinavir inhibit the hydroxylation of bupropion.
Inhibitors of CYP2B6
Ticlopidine and Clopidogrel: In a study in healthy male volunteers, clopidogrel 75 mg once daily or ticlopidine 250 mg twice daily increased exposures (Cmax and AUC) of bupropion by 40% and 60% for clopidogrel, by 38%and 85% for ticlopidine, respectively. The exposures of hydroxybupropion were decreased.
Prasugrel: In healthy subjects, prasugrel increased bupropion Cmax and AUC values by 14% and 18%, respectively, and decreased Cmax and AUC values of hydroxybupropion by 32% and 24%, respectively.
Cimetidine: Following oral administration of bupropion 300 mg with and without cimetidine 800 mg in 24 healthy young male volunteers, the pharmacokinetics of bupropion and hydroxybupropion were unaffected. However, there were 16% and 32% increases in the AUC and Cmax, respectively, of the combined moieties of threohydrobupropion and erythrohydrobupropion.
Citalopram: Citalopram did not affect the pharmacokinetics of bupropion and its three metabolites.
Inducers of CYP2B6
Ritonavir and Lopinavir: In a healthy volunteer study, ritonavir 100 mg twice daily reduced the AUC and Cmax of bupropion by 22% and 21%, respectively. The exposure of the hydroxybupropion metabolite was decreased by 23%, the threohydrobupropion decreased by 38%, and the erythrohydrobupropion decreased by 48%.In a second healthy volunteer study, ritonavir 600 mg twice daily decreased the AUC and Cmax of bupropion by 66% and 62%, respectively. The exposure of the hydroxybupropion metabolite was decreased by 78%, the threohydrobupropion decreased by 50%, and the erythrohydrobupropion decreased by 68%.
In another healthy volunteer study, lopinavir 400 mg/ritonavir 100 mg twice daily decreased bupropion AUC and Cmax by 57%. The AUC and Cmax of hydroxybupropion metabolite were decreased by 50% and 31%, respectively.
Efavirenz: In a study of healthy volunteers, efavirenz 600 mg once daily for 2 weeks reduced the AUC and Cmax of bupropion by approximately 55% and 34%, respectively. The AUC of hydroxybupropion was unchanged, whereas Cmax of hydroxybupropion was increased by 50%.
Carbamazepine, Phenobarbital, Phenytoin: While not systematically studied, these drugs may induce the metabolism of bupropion.
Potential for Bupropion Hydrochloride to Affect Other Drugs
Animal data indicated that bupropion may be an inducer of drug-metabolizing enzymes in humans. In a study of 8 healthy male volunteers, following a 14-day administration of bupropion 100 mg three times per day, there was no evidence of induction of its own metabolism. Nevertheless, there may be the potential for clinically important alterations of blood levels of coadministered drugs.
Drugs Metabolized by CYP2D6
In vitro, bupropion and hydroxybupropion are CYP2D6 inhibitors. In a clinical study of 15 male subjects (ages 19 to 35 years) who were extensive metabolizers of CYP2D6, bupropion given as 150 mg twice daily followed by a single dose of 50 mg desipramine increased the Cmax , AUC, and T½ of desipramine by an average of approximately 2-, 5-, and 2-fold, respectively. The effect was present for at least 7 days after the last dose of bupropion. Concomitant use of bupropion with other drugs metabolized by CYP2D6 has not been formally studied.
Citalopram: Although citalopram is not primarily metabolized by CYP2D6, in one study bupropion increased the Cmax and AUC of citalopram by 30% and 40%, respectively.
Lamotrigine: Multiple oral doses of bupropion had no statistically significant effects on the single-dose pharmacokinetics of lamotrigine in 12 healthy volunteers.
Suicidal Thoughts and Behaviors
Instruct patients, their families, and/or their caregivers to be alert to the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behavior, worsening of depression, and suicidal ideation, especially early during antidepressant treatment and when the dose is adjusted up or down. Advise families and caregivers of patients to observe for the emergence of such symptoms on a day-to-day basis, since changes may be abrupt. Such symptoms should be reported to the patient's prescriber or health professional, especially if they are severe, abrupt in onset, or were not part of the patient's presenting symptoms. Symptoms such as these may be associated with an increased risk for suicidal thinking and behavior and indicate a need for very close monitoring and possibly changes in the medication.
Neuropsychiatric Adverse Events and Suicide Risk in Smoking Cessation Treatment
Although bupropion hydrochloride extended-release tablets (XL) is not indicated for smoking cessation treatment, it contains the same active ingredient as ZYBAN which is approved for this use. Inform patients that some patients have experienced changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation and suicide when attempting to quit smoking while taking bupropion. Instruct patients to discontinue bupropion hydrochloride extended-release tablets (XL) and contact a healthcare professional if they experience such symptoms [see Warnings and Precautions (5.2), Adverse Reactions (6.2)].
Severe Allergic Reactions
Educate patients on the symptoms of hypersensitivity and to discontinue bupropion hydrochloride extended-release tablets (XL) if they have a severe allergic reaction.
Seizure
Instruct patients to discontinue and not restart bupropion hydrochloride extended-release tablets (XL) if they experience a seizure while on treatment. Advise patients that the excessive use or the abrupt discontinuation of alcohol, benzodiazepines, antiepileptic drugs, or sedatives/hypnotics can increase the risk of seizure. Advise patients to minimize or avoid the use of alcohol.
Angle-Closure Glaucoma
Patients should be advised that taking bupropion hydrochloride extended-release tablets (XL) can cause mild pupillary dilation, which in susceptible individuals, can lead to an episode of angle-closure glaucoma. Pre-existing glaucoma is almost always open-angle glaucoma because angle-closure glaucoma, when diagnosed, can be treated definitively with iridectomy. Open-angle glaucoma is not a risk factor for angle-closure glaucoma. Patients may wish to be examined to determine whether they are susceptible to angle closure, and have a prophylactic procedure (e.g., iridectomy), if they are susceptible [see Warnings and Precautions (5.7)].
Bupropion-Containing Products
Educate patients that bupropion hydrochloride extended-release tablets (XL) contains the same active ingredient (bupropion) found in ZYBAN, which is used as an aid to smoking cessation treatment, and that bupropion hydrochloride extended-release tablets (XL) should not be used in combination with ZYBAN or any other medications that contain bupropion hydrochloride (such as WELLBUTRIN SR, the sustained-release formulation, WELLBUTRIN, the immediate-release formulation, and APLENZIN, a bupropion hydrobromide formulation). In addition, there are a number of generic bupropion HCl products for the immediate, sustained, and extended-release formulations.
Potential for Cognitive and Motor Impairment
Advise patients that any CNS-active drug like bupropion hydrochloride extended-release tablets (XL) may impair their ability to perform tasks requiring judgment or motor and cognitive skills. Advise patients that until they are reasonably certain that bupropion hydrochloride extended-release tablets (XL) do not adversely affect their performance, they should refrain from driving an automobile or operating complex, hazardous machinery. Bupropion hydrochloride extended-release tablets (XL) treatment may lead to decreased alcohol tolerance.
Concomitant Medications
Counsel patients to notify their healthcare provider if they are taking or plan to take any prescription or over-the-counter drugs, because bupropion hydrochloride extended-release tablets (XL) and other drugs may affect each other's metabolism.
Pregnancy
Advise patients to notify their healthcare provider if they become pregnant or intend to become pregnant during therapy with bupropion hydrochloride extended-release tablets (XL). Advise patients that there is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to bupropion hydrochloride extended-release tablets (XL) during pregnancy [see Use in Specific Populations (8.1)].
Administration Information
Instruct patients to swallow bupropion hydrochloride extended-release tablets (XL) whole so that the release rate is not altered. Instruct patients if they miss a dose, not to take an extra tablet to make up for the missed dose and to take the next tablet at the regular time because of the dose-related risk of seizure. Instruct patients that bupropion hydrochloride extended-release tablets (XL) should be swallowed whole and not crushed, divided, or chewed. Bupropion hydrochloride extended-release tablets (XL) should be administered in the morning and may be taken with or without food.
Manufactured by:
Hangzhou Minsheng Binjiang Pharmaceutical Co., Ltd.
658 Bin'an Road Binjiang District, Hangzhou, Zhejiang 310051, China
Manufactured for:
Mullan Pharmaceutical Inc.
Pasadena, California 91101, USA
All other product/brand names and/or logos are the trademarks of the respective owners.
Rev. 05/2024