A comparison of the analgesic effects of methotrimeprazine and morphine in patients with cancer

Abstract

A double‐blind crossover evaluation of the relative analgesic potency of graded intramuscular doses of methotrimeprazine and morphine was carried out in patients with cancer. The configurations of the time‐effect curves of the two drugs appeared to be similar. Considering either “total” or “peak” effects, the analgesic potency of methotrimeprazine is estimated to be approximately one half that of morphine. A significantly larger number of patients had side effects with methotrimeprazine than with morphine, and this was largely due to the pronounced sedative effect of methotrimeprazine. Nausea and vomiting were much less frequent following administration of methotrimeprazine than morphine.