Nabilone is a synthetic cannabinoid with antiemetic properties which have been found to be of value in the management of some patients with nausea and vomiting associated with cancer chemotherapy. It also has sedative and psychotropic effects.
After oral administration, comparable peak plasma levels of nabilone and of its carbinol metabolite were attained within 2 hours. The combined plasma concentrations of nabilone and of its carbinol metabolite accounted for, at most, 10 to 20% of the total radio-carbon concentration in plasma. The plasma half life of nabilone was approximately 2 hours, while that of the total radiocarbon was of the order of 35 hours.
Of the 2 major possible metabolic pathways, stereo-specific enzymatic reduction and direct enzymatic oxidation, the latter appears to be the more important in man.
The drug and its metabolites are eliminated mainly in the feces (approximately 65%) and to a lesser extent in the urine (approximately 20%). The major excretory pathway is the biliary system.
Indications And Clinical Uses: For the management of severe nausea and vomiting associated with cancer chemotherapy.
Contra-Indications: Sensitivity to marijuana or other cannabinoid agents, and in patients with a history of psychotic reactions. tag_WarningWarnings
Manufacturers' Warnings In Clinical States: Nabilone should be used with extreme caution in patients with severe liver dysfunction and in those with a history of non-psychotic emotional disorders.
Nabilone should not be taken with alcohol, sedatives, hypnotics, or other psychotomimetic substances.
Pregnancy, Lactation and Children: Nabilone should not be used during pregnancy, in nursing mothers or in pediatric patients, since its safety under these conditions has not been established.
Precautions: Occupational Hazards: Since nabilone will often impair the mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a car and operating machinery, the patient should be warned accordingly and should not be permitted to drive or engage in dangerous tasks until the effects of nabilone are no longer present.
Adverse psychiatric reactions can persist for 48 to 72 hours following cessation of treatment.
Since nabilone elevates supine and standing heart rates and causes postural hypotension, it should be used with caution in the elderly and in patients with hypertension or heart disease.
Drug Interactions: Potential interactions between nabilone, and diazepam sodium secobarbital alcohol or codeine were evaluated. The depressant effects of the combinations were additive. Psychomotor function was particularly impaired with concurrent use of diazepam.
Adverse Reactions: The most frequently observed adverse reactions to nabilone and their incidences reported in the course of clinical trials were as follows: drowsiness (66.0%), vertigo (58.8%), psychological high (38.8%), dry mouth (21.6%), depression (14.0%), ataxia (12.8%), blurred vision (12.8%), sensation disturbance (12.4%), anorexia (7.6%), asthenia (7.6%), headache (7.2%), orthostatic hypotension (5.2%), euphoria (4.0%) and hallucinations (2.0%).
The following adverse reactions were observed in less than 1% of the patients who were administered nabilone in the course of the clinical trials: tachycardia, tremors, syncope, nightmares, distortion in the perception of time, confusion, dissociation, dysphoria, psychotic reactions and seizures.
Spontaneously Reported Adverse Events: The following adverse reactions listed in order of decreasing frequency by body system have been reported since nabilone has been marketed. All events are listed regardless of causality assessment.
Blood and Hematopoietic: leukopenia.
Cardiovascular: hypotension and tachycardia.
Eye and Ear: visual disturbances.
Gastrointestinal: dry mouth, nausea, vomiting and constipation.
CNS: hallucinations, CNS depression, CNS stimulation, ataxia, stupor, vertigo, convulsion and circumoral paresthesia.
Psychiatric: somnolence, confusion, euphoria, depression. dysphoria, depersonalization, anxiety, psychosis and emotional lability.
Miscellaneous and Ill-Defined Conditions: dizziness, headache, insomnia, abnormal thinking, chest pain, lack of effect, and face edema.
Symptoms And Treatment Of Overdose: Symptoms: Signs and symptoms which might be expected to occur are psychotic episodes including hallucinations, anxiety reactions, respiratory depression and coma (experience with cases of overdosage of more than 10 mg/day has not yet been reported). tag_Treatment
Treatment: Overdose may be considered to have occurred, even at prescribed dosages, if disturbing psychiatric symptoms are present. In these cases, the patient should be observed in a quiet environment and supportive measures, including reassurance, should be used. Subsequent doses should be withheld until patients have returned to their baseline mental status
