delta 9-Tetrahydrocannabinol as an antiemetic for patients receiving cancer chemotherapy. A pilot study.

We conducted a pilot study to ascertain the potential toxicity and possible efficacy of delta 9-tetrahydrocannabinol (THC) at the oral dose of 5 mg/m2. Over one third of the study population, which consisted of 25 patients, reported significant dysphoric reactions. Four patients (16 per cent) elected not to take THC rather than experience loss of motivation which interfered with their professional life. Paradoxically, on eight occasions nausea seemed to worsen with THC. After the first administration of THC, 18 patients (72 per cent) described less nausea and only two individuals (8 per cent) noted complete resolution of nausea. Two patients reported worsening of their nausea. Eighteen patients noted less vomiting (69 per cent) after the first administration of THC and four patients (15 per cent) reported completed resolution of their vomiting. By the third administration of THC, one of 14 patients (7 per cent) and two of 14 (14 per cent) noted complete alleviation of nausea and vomiting, respectively. Patients who scored high on the Brief Psychiatric Rating Scale, who reported euphoria, or who had psychogenic nausea and vomiting were most likely to have a favorable antiemetic response. The results of this pilot study suggest that orally administered THC is a toxic but transiently effective antiemetic when administered at 5 mg/m2.