delta 9-Tetrahydrocannabinol for refractory vomiting induced by cancer chemotherapy.

Fifty-three patients receiving antineoplastic chemotherapy who had experienced severe nausea and vomiting refractory to standard antiemetic agents were treated with delta 9-tetrahydrocannabinol (THC). These patients were given THC 8 to 12 hours before, during, and for 24 hours after chemotherapy. Ten patients (19%) had no further nausea and vomiting; 28 (53%) had at least a 50% reduction of nausea and vomiting compared to previous courses with the same agents. No appreciable reduction of nausea and vomiting was seen in 15 patients (28%). Toxic reactions were generally mild, with only four patients experiencing reactions that necessitated stopping THC therapy. We suggest that, since THC is a useful antimetic agent in patients having refractory chemotherapy-induced vomiting, existing restrictions prohibiting its therapeutic use should promptly be eased.