Starting Dosage
The recommended adult starting dosage of dronabinol capsules is 2.5 mg orally twice daily, one hour before lunch and dinner.
In elderly patients or patients unable to tolerate 2.5 mg twice daily, consider initiating dronabinol capsules at 2.5 mg once daily one hour before dinner or at bedtime to reduce the risk of central nervous system (CNS) symptoms [see Use in Specific Populations (8.5)].
Dosing later in the day may reduce the frequency of CNS adverse reactions. CNS adverse reactions are dose-related [see Warnings and Precautions (5.1)]; therefore, monitor patients and reduce the dosage as needed. If CNS adverse reactions of feeling high, dizziness, confusion, and somnolence occur, they usually resolve in 1 to 3 days and usually do not require dosage reduction. If CNS adverse reactions are severe or persistent, reduce the dosage to 2.5 mg in the evening or at bedtime.
Dosage Titration
If tolerated and further therapeutic effect is desired, the dosage may be increased gradually to 2.5 mg one hour before lunch and 5 mg one hour before dinner. Increase the dose of dronabinol capsules gradually in order to reduce the frequency of dose-related adverse reactions [see Warnings and Precautions (5.1)].
Most patients respond to 2.5 mg twice daily, but the dose may be further increased to 5 mg one hour before lunch and 5 mg one hour before dinner, as tolerated to achieve a therapeutic effect.
Maximum Dosage: 10 mg twice daily.
Starting Dosage
The recommended starting dosage of dronabinol capsules is 5 mg/m2, orally administered 1 to 3 hours prior to the administration of chemotherapy and then every 2 to 4 hours after chemotherapy, for a total of 4 to 6 doses per day.
In elderly patients, consider initiating dronabinol capsules at 2.5 mg/m2 once daily 1 to 3 hours prior to chemotherapy to reduce the risk of CNS symptoms [see Use in Specific Populations (8.5)].
Administer the first dose on an empty stomach at least 30 minutes before eating. Subsequent doses can be taken without regard to meals [see Clinical Pharmacology (12.3)].
The timing of dosing in relation to meal times should be kept consistent for each chemotherapy cycle, once the dosage has been determined from the titration process.
Dosage Titration
The dosage can be titrated to clinical response during a chemotherapy cycle or subsequent cycles, based upon initial response, as tolerated to achieve a clinical effect, in increments of 2.5 mg/m2.
The maximum dosage is 15 mg/m2 per dose for 4 to 6 doses per day.
Adverse reactions are dose-related and psychiatric symptoms increase significantly at the maximum dosage [see Warnings and Precautions (5.1)].
Monitor patients for adverse reactions and consider decreasing the dose to 2.5 mg once daily 1 to 3 hours prior to chemotherapy to reduce the risk of CNS adverse reactions.
Psychiatric Adverse Reactions
Dronabinol has been reported to exacerbate mania, depression, or schizophrenia. Significant CNS symptoms followed oral doses of 0.4 mg/kg (28 mg per 70 kg patient) of dronabinol capsules in antiemetic studies.
Prior to initiating treatment with dronabinol capsules, screen patients for a history of these illnesses. Avoid use in patients with a psychiatric history or, if the drug cannot be avoided, monitor patients for new or worsening psychiatric symptoms during treatment. Also, avoid concomitant use with other drugs that are associated with similar psychiatric effects.
Cognitive Adverse Reactions
Use of dronabinol capsules has been associated with cognitive impairment and altered mental state. Reduce the dose of dronabinol capsules or discontinue use of dronabinol capsules if signs or symptoms of cognitive impairment develop. Elderly patients may be more sensitive to the neurological and psychoactive effects of dronabinol capsules [see Use in Specific Populations (8.4, 8.5)].
Hazardous Activities
Dronabinol capsules can cause and may impair the mental and/or physical abilities required for the performance of hazardous tasks such as driving a motor vehicle or operating machinery. Concomitant use of other drugs that cause dizziness, confusion, sedation, or somnolence such as CNS depressants may increase this effect (e.g., barbiturates, benzodiazepines, ethanol, lithium, opioids, buspirone, scopolamine, antihistamines, tricyclic antidepressants, other anticholinergic agents, muscle relaxants). Inform patients not to operate motor vehicles or other dangerous machinery until they are reasonably certain that dronabinol capsules do not affect them adversely.
Common Adverse Reactions
The following adverse reactions were reported in clinical trials at an incidence greater than 1%.
| System Organ Class | Adverse Reactions |
|---|
| General | Asthenia |
| Cardiovascular | Palpitations, tachycardia, vasodilation/facial flush |
| Gastrointestinal | Abdominal pain Actual incidence 3% to 10% , nausea, vomiting |
| Central Nervous System | Dizziness, euphoria, paranoid reaction, somnolence, thinking abnormal, amnesia, anxiety/nervousness, ataxia, confusion, depersonalization, hallucination |
Less Common Adverse Reactions
The following adverse reactions were reported in clinical trials at an incidence less than or equal to 1%.
| System Organ Class | Adverse Reactions |
|---|
| General | Chills, headache, malaise |
| Cardiovascular | Hypotension, conjunctival injection [see Clinical Pharmacology (12.2)] |
| Gastrointestinal | Diarrhea, fecal incontinence, anorexia, hepatic enzyme elevation |
| Musculoskeletal | Myalgias |
| Central Nervous System | Depression, nightmares, speech difficulties, tinnitus |
| Respiratory | Cough, rhinitis, sinusitis |
| Skin | Flushing, sweating |
| Sensory | Vision difficulties |
Risk Summary
Dronabinol capsules, a synthetic cannabinoid, may cause fetal harm. Avoid use of dronabinol capsules in pregnant women. Although there is little published data on the use of synthetic cannabinoids during pregnancy, use of cannabis (e.g., marijuana) during pregnancy has been associated with adverse fetal/neonatal outcomes [see Clinical Considerations]. Cannabinoids have been found in the umbilical cord blood from pregnant women who smoke cannabis. In animal reproduction studies, no teratogenicity was reported in mice administered dronabinol at up to 30 times the MRHD (maximum recommended human dose) and up to 5 times the MRHD for patients with AIDS and cancer, respectively. Similar findings were reported in pregnant rats administered dronabinol at up to 5 to 20 times the MRHD and 3 times the MRHD for patients with AIDS and cancer, respectively. Decreased maternal weight gain and number of viable pups and increased fetal mortality and early resorptions were observed in both species at doses which induced maternal toxicity. In published studies, offspring of pregnant rats administered delta-9-THC during and after organogenesis have been reported to exhibit neurotoxicity with adverse effects on brain development, including abnormal neuronal connectivity and impairments in cognitive and motor function [see Data].
The estimated background risk of major birth defects and miscarriage for the indicated populations are unknown. All pregnancies have a background risk 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
Fetal/Neonatal Adverse Reactions
Published studies suggest that during pregnancy, the use of cannabis, which includes THC, whether for recreational or medicinal purposes, may increase the risk of adverse fetal/neonatal outcomes including fetal growth restriction, low birth weight, preterm birth, small-for-gestational age, admission to the NICU, and stillbirth. Therefore, use of cannabis during pregnancy should be avoided.
Data
Human Data
Delta-9-THC has been measured in the cord blood of some infants whose mothers reported prenatal use of cannabis, suggesting that dronabinol may cross the placenta to the fetus during pregnancy. The effects of delta-9-THC on the fetus are not known.
Animal Data
Reproduction studies with dronabinol have been performed in mice at 15 to 450 mg/m2, equivalent to 1 to 30 times the MRHD of 15 mg/m2/day in AIDS patients or 0.2 to 5 times the MRHD of 90 mg/m2/day in cancer patients, and in rats at 74 to 295 mg/m2 (equivalent to 5 to 20 times the MRHD of 15 mg/m2/day in AIDS patients or 0.8 to 3 times the MRHD of 90 mg/m2/day in cancer patients). These studies have revealed no evidence of teratogenicity due to dronabinol. At these dosages in mice and rats, dronabinol decreased maternal weight gain and number of viable pups and increased fetal mortality and early resorptions. Such effects were dose dependent and less apparent at lower doses that produced less maternal toxicity.
Review of published literature indicates that the endocannabinoid system plays a role in neurodevelopmental processes such as neurogenesis, migration, and synaptogenesis. Exposure of pregnant rats to delta-9-THC (during and after organogenesis) may modulate these processes to result in abnormal patterns of neuronal connectivity and subsequent cognitive impairments in the offspring. Nonclinical toxicity studies in pregnant rats and newborn pups have shown prenatal exposure to THC that resulted in impairment of motor function, alteration in synaptic activity, and interference in cortical projection of neuron development in the offspring. Prenatal exposure has shown effects on cognitive function such as learning, short-and long-term memory, attention, decreased ability to remember task, and ability to discriminate between novel and same objects. Overall, prenatal exposure to THC has resulted in significant and long-term changes in brain development, cognition, and behavior in rat offspring.
Risk Summary
For mothers infected with the Human Immunodeficiency Virus (HIV), the Centers for Disease Control and Prevention recommends that HIV-infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV. Because of the potential for HIV transmission (in HIV-negative infants) and serious adverse reactions in a breastfed infant, instruct mothers not to breastfeed if they are receiving dronabinol capsules.
For mothers with nausea and vomiting associated with cancer chemotherapy, there are limited data on the presence of dronabinol in human milk, the effects on the breastfed infant, or the effects on milk production. The reported effects of inhaled cannabis transferred to the breastfeeding infant have been inconsistent and insufficient to establish causality. Because of the possible adverse effects from dronabinol capsules on the breastfeeding infant, advise women with nausea and vomiting associated with cancer chemotherapy not to breastfeed during treatment with dronabinol capsules and for 9 days after the last dose.
Effects on the Cardiovascular System
Dronabinol-induced sympathomimetic activity may result in tachycardia and/or conjunctival injection. Its effects on blood pressure are inconsistent, but subjects have experienced orthostatic hypotension and/or syncope upon abrupt standing [see Warnings and Precautions (5.2)].
Effects on the Central Nervous System
Dronabinol also demonstrates reversible effects on appetite, mood, cognition, memory, and perception. These phenomena appear to be dose-related, increasing in frequency with higher dosages, and subject to great inter-patient variability. After oral administration, dronabinol has an onset of action of approximately 0.5 to 1 hours and peak effect at 2 to 4 hours. Duration of action for psychoactive effects is 4 to 6 hours, but the appetite stimulant effect of dronabinol may continue for 24 hours or longer after administration.
Tachyphylaxis and tolerance develop to some of the pharmacologic effects of dronabinol with chronic use, suggesting an indirect effect on sympathetic neurons. In a study of the pharmacodynamics of chronic dronabinol exposure, healthy male subjects (N = 12) received 210 mg per day of dronabinol capsules, administered orally in divided doses, for 16 days. An initial tachycardia induced by dronabinol was replaced successively by normal sinus rhythm and then bradycardia. A decrease in supine blood pressure, made worse by standing, was also observed initially. These subjects developed tolerance to the cardiovascular and subjective adverse CNS effects of dronabinol within 12 days of treatment initiation.
Tachyphylaxis and tolerance do not appear to develop to the appetite stimulant effect of dronabinol capsules. In clinical studies involving AIDS patients, the appetite stimulant effect of dronabinol capsules was sustained for up to five months at dosages ranging from 2.5 mg to 20 mg per day.
Absorption
Dronabinol (delta-9-THC) is almost completely absorbed (90 to 95%) after single oral doses. Due to the combined effects of first pass hepatic metabolism and high lipid solubility, only 10 to 20% of the administered dose reaches the systemic circulation. Concentrations of both parent drug and its major active metabolite (11-hydroxy-delta-9-THC) peak at approximately 0.5 to 4 hours after oral dosing and decline over several days.
The pharmacokinetics of dronabinol after single doses (2.5, 5, and 10 mg) and multiple doses (2.5, 5, and 10 mg given twice a day) have been studied in healthy subjects.
Summary of Multiple-Dose Pharmacokinetic Parameters of Dronabinol in Healthy Subjects (n=34; 20 to 45 years) under Fasted Conditions| Mean (SD) PK Parameter Values |
|---|
| Twice Daily Dose | Cmax ng/mL | Median Tmax (range), hr | AUC(0-12) ng∙hr/mL |
|---|
| Cmax: maximum observed plasma concentration; Tmax: time to maximum observed plasma concentration; AUC(0-12): area under the plasma concentration-time curve from 0 to 12 hours. |
| 2.5 mg | 1.32 (0.62) | 1.00 (0.50-4.00) | 2.88 (1.57) |
| 5 mg | 2.96 (1.81) | 2.50 (0.50-4.00) | 6.16 (1.85) |
| 10 mg | 7.88 (4.54) | 1.50 (0.50-3.50) | 15.2 (5.52) |
A slight increase in dose proportionality on mean Cmax and AUC(0-12) of dronabinol was observed with increasing dose over the dose range studied.
Effect of Food
In a published study, the effect of food on the pharmacokinetics of dronabinol was studied by concomitant dosing of dronabinol capsules with a high-fat (59 grams of fat, approximately 50% of total caloric content of the meal), high calorie meal (approximately 950 calories). An appreciable food effect was observed, resulting in a 4-hour delay in mean Tmax and 2.9-fold increase in total exposure (AUCinf), but Cmax was not significantly changed [see Dosage and Administration (2.2)].
Distribution
Dronabinol has an apparent volume of distribution of approximately 10 L/kg, because of its lipid solubility. The plasma protein binding of dronabinol and its metabolites is approximately 97% [see Drug Interactions (7.4)].
Elimination
The pharmacokinetics of dronabinol can be described using a two-compartment model with an initial (alpha) half-life of about 4 hours and a terminal (beta) half-life of 25 to 36 hours. Values for clearance average about 0.2 L/kg-hr, but are highly variable due to the complexity of cannabinoid distribution.
Metabolism
Dronabinol undergoes extensive first-pass hepatic metabolism, primarily by hydroxylation, yielding both active and inactive metabolites. Dronabinol and its principal active metabolite, 11hydroxy-delta-9-THC, are present in approximately equal concentrations in plasma. Published in vitro data indicates that CYP2C9 and CYP3A4 are the primary enzymes in the metabolism of dronabinol. CYP2C9 appears to be the enzyme responsible for the formation of the primary active metabolite [see Clinical Pharmacology (12.5)].
Excretion
Dronabinol and its biotransformation products are excreted in both feces and urine. Biliary excretion is the major route of elimination with about half of a radiolabeled oral dose being recovered from the feces within 72 hours as contrasted with 10 to 15% recovered from urine. Less than 5% of an oral dose is recovered unchanged in the feces.
Due to its re-distribution, dronabinol and its metabolites may be excreted at low levels for prolonged periods of time. Following single dose administration, low levels of dronabinol metabolites have been detected for more than 5 weeks in the urine and feces.
In a study of dronabinol capsules involving AIDS patients, urinary cannabinoid/creatinine concentration ratios were studied bi-weekly over a six-week period. The urinary cannabinoid/creatinine ratio was closely correlated with dose. No increase in the cannabinoid/creatinine ratio was observed after the first two weeks of treatment, indicating that steady-state cannabinoid levels had been reached. This conclusion is consistent with predictions based on the observed terminal half-life of dronabinol.
Drug Interaction Studies
Formal drug-drug interaction studies have not been conducted with dronabinol.
The enzyme inhibition and induction potential of dronabinol and its active metabolite are not completely understood.
Published data showed an increase in the elimination half-life of pentobarbital by 4 hours when concomitantly dosed with dronabinol [see Warnings and Precautions (5.1)].
Neuropsychiatric Adverse Reactions [see Warnings and Precautions (5.1)]
- Advise patients that psychiatric adverse reactions may occur, especially in patients with a past psychiatric history or in those receiving other drugs also associated with psychiatric effects, and to report to their healthcare provider any new or worsening psychiatric symptoms.
- Advise patients, especially elderly patients, that cognitive impairment or an altered mental state may also occur during treatment with dronabinol capsules and to report to their healthcare provider if they develop signs or symptoms of cognitive impairment.
- Advise patients not to operate motor vehicles or other dangerous machinery until they are reasonably certain that dronabinol capsules do not affect them adversely. Alert patients to the potential for additive central nervous system depression if dronabinol capsules are used concomitantly with alcohol or other CNS depressants such as benzodiazepines and barbiturates.
Hemodynamic Instability
Advise patients, especially those with cardiac disorders, to report to their healthcare provider if they experience any signs or symptoms of hemodynamic instability, including hypotension, hypertension, syncope, or tachycardia, especially after initiating or increasing the dosage of dronabinol capsules [see Warnings and Precautions (5.2)].
Seizures
Advise patients to discontinue dronabinol capsules and contact a healthcare provider immediately if they experience a seizure [see Warnings and Precautions (5.3)].
Multiple Substance Abuse
Inform patients with a history of substance abuse or dependence, including marijuana or alcohol, that they may be more likely to abuse dronabinol capsules. Advise patients to report to their healthcare provider if they develop abuse behaviors or conditions [see Warnings and Precautions (5.4)].
Paradoxical Nausea, Vomiting, or Abdominal Pain
Advise patients to report worsening nausea, vomiting or abdominal pain to their healthcare provider [see Warnings and Precautions (5.5)].
Pregnancy
Advise pregnant women of the potential risk to a fetus and to avoid use of dronabinol capsules during pregnancy [see Use in Specific Populations (8.1)].
Lactation
- Advise HIV infected women with anorexia associated with weight loss, not to breastfeed.
- Advise women with nausea and vomiting associated with cancer chemotherapy not to breastfeed during treatment with dronabinol capsules and for 9 days after the last dose [see Use in Specific Populations (8.2)].
Manufactured by:
Pharmaceutics International, Inc.
Hunt Valley, MD 21031
Marketed by:
Rhodes Pharmaceuticals L.P.
Coventry, RI 02816
304703-0B
August 2018