Cannabinoids and the control of chemotherapy-induced nausea and vomiting

The major progress in controlling chemotherapy-induced emesis benefits thou sands of patients each day. Antiemetic efficacy is found with agents of man y different classes, including phenothiazines, butyrophenones, cannabinoids , corticosteroids, substituted benzamides, and serotonin receptor antagonis ts. To date, the most effective antiemetic regimens are combinations of ser otonin-receptor antagonists with corticosteroids. Most antiemetic studies with cannabinoids have methodological difficulties and can be difficult to interpret. If one concentrates on the better-conduc ted trials, however, it is clear that cannabinoids possess antiemetic prope rties in patients receiving cancer chemotherapy The degree of antiemetic ac tivity demonstrated by cannabinoids is not as high as that seen with severa l other classes of agents. The side effects associated with cannabinoid use are tolerable, but greater that those seen with other classes of agents. Studies have not demonstrated an advantage of one tested cannabinoid over a nother. Results of trials with synthetic cannabinoids, such as levonantrado l or nabilone, do not indicate a superior therapeutic index over naturally occurring cannabinoids. Only limited data from well-designed trials can be found comparing inhalant marihuana with other cannabinoids. From that which exists, there is no clear advantage for either inhalant marihuana or for o ral THC. Additionally, there is no demonstration that the inhalant agent re sults in an improved pharmacokinetic profile, an advantage in self titratio n, or in a different pattern of side effects. Further studies with cannabinoids, using accepted methodology could more ac curately outline their activity. Decisions should be made whether or not th e current moderate degree of efficacy and moderate amount of associated sid e effects with all tested cannabinoid antiemetics warrant such trials in th e context of substantially more active agents that have more favorable toxi city profiles.