One systematic review studied 30 randomized comparisons of delta-9-THC preparations with placebo or other antiemetics from which data on efficacy and harm were available. Oral nabilone, oral dronabinol, and intramuscular levonantradol (a synthetic analog of dronabinol) were tested. Inhaled Cannabis trials were not included. Among all 1,366 patients included in the review, cannabinoids were found to be more effective than the conventional antiemetics prochlorperazine, metoclopramide, chlorpromazine, thiethylperazine, haloperidol, domperidone, and alizapride. Cannabinoids, however, were not more effective for patients receiving very low or very high emetogenic chemotherapy. Side effects included a feeling of being high, euphoria, sedation or drowsiness, dizziness, dysphoria or depression, hallucinations, paranoia, and hypotension. Newer antiemetics (e.g., 5-HT3 receptor antagonists) have not been directly compared with Cannabis or cannabinoids in cancer patients.
Another analysis of 15 controlled studies compared nabilone with placebo or available antiemetic drugs. Among 600 cancer patients, nabilone was found to be superior to prochlorperazine, domperidone, and alizapride, with nabilone favored for continuous use.
(Refer to the Cannabis section in the PDQ summary on Nausea and Vomiting for more information.)
Three trials have evaluated the efficacy of inhaled marijuana in chemotherapy-induced N/V.[22,23,24] In two of the studies, inhaled Cannabis was made available only after dronabinol failure. In the first trial, no antiemetic effect was achieved with marijuana in patients receiving cyclophosphamide or doxorubicin, but in the second trial, a statistically significant superior antiemetic effect of inhaled Cannabis versus placebo was found among patients receiving high-dose methotrexate. The third trial was a randomized, double-blind, placebo-controlled cross-over trial involving 20 adults in which both inhaled marijuana and oral THC were evaluated. One-quarter of the patients reported a favorable antiemetic response to the cannabinoid therapies. This latter study was reported in abstract form in 1984. A full report, detailing the methods and outcomes apparently has not been published, which limits a thorough interpretation of the significance of these findings.
Anorexia, early satiety, weight loss, and cachexia are problems experienced by cancer patients. Such patients are faced not only with the disfigurement associated with wasting but also with an inability to engage in the social interaction of meals.