| Indication |
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. |
| Pharmacodynamics |
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. |
| Absorption |
Rapidly absorbed from the gastrointestinal tract following oral administration. |
| Volume of distribution |
|
| Protein binding |
Not Available |
| 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. |
| Route of elimination |
The route and rate of the elimination of nabilone and its
metabolites are similar to those observed with other cannabinoids,
including delta-9-THC (dronabinol). Therefore, it appears that the major
excretory pathway is the biliary system. |
| Half life |
2 hours, with metabolites around 35 hours. |
| Clearance |
Not Available |
| Toxicity |
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. |
