Brands, Medical Use, Clinical Data
- Anti-Anxiety Agents
Brands / Synonyms
Used for the control of nausea and vomiting, caused by chemotherapeutic agents used in the treatment of cancer, in patients who have failed to respond adequately to conventional antiemetic treatments.
Nabilone is a cannabinoid with therapeutic uses. It is an analog of dronabinol (also known as tetrahydrocannabinol or THC), the psychoactive ingredient in cannabis. It is reserved for use in individuals who do not respond to the more commonly used anti-emetics. This is mainly because cannabinoids have potential adverse effects similar to that of cannabis and may cause changes in mood and behaviour.
Mechanism of Action
The mode of action of nabilone has been studied in cats and dogs. Although its anti-emetic action is not yet fully understood, it is apparent that there are a number of points in the control systems of the body at which Nabilone could block the emetic mechanism. It is likely that nabilone exerts its actions via binding to the cannabinoid receptors.
Rapidly absorbed from the gastrointestinal tract following oral administration.
Symptoms of overdose include difficulty in breathing, hallucinations, mental changes (severe), nervousness or anxiety (severe). Monkeys treated with Nabilone at doses as high as 2mg/kg/day for a year experienced no significant adverse events. This result contrasts with the finding in a planned 1-year dog study that was prematurely terminated because of deaths associated with convulsions in dogs receiving as little as 0.5mg/kg/day. The earliest deaths, however, occurred at 56 days in dogs receiving 2mg/kg/day. The unusual vulnerability of the dog is not understood; it is hypothesised, however, that the explanation lies in the fact that the dog differs markedly from other species (including humans) in its metabolism of Nabilone.
Biotrnasformation / Drug Metabolism
Hepatic. Two metabolic pathways have been suggested. The major pathway probably involves the direct oxidation of Nabilone to produce hydroxylic and carboxylic analogues. These compounds are thought to account for the remaining plasma radioactivity when carbinol metabolites have been extracted.
Nabilone is contra-indicated in patients with a known allergy to cannabinoid agents and when the nausea and vomiting arises from any cause other than cancer chemotherapy.
Nabilone should be administered with caution to patients who are taking other psychoactive drugs or CNS depressants, including alcohol, barbiturates and narcotic analgesics, or to those with a history of psychiatric disorder (including manic-depressive illness and schizophrenia). Nabilone has been shown to have an additive CNS depressant effect when given with either diazepam, secobarbitone sodium, alcohol or codeine.