COMPARATIVE ANALGESIC ACTIVITY OF LEVOMEPROMAZINE AND MORPHINE IN PATIENTS WITH CHRONIC PAIN

Apart from its ability to potentiate the action of narcotics, levomepromazine, a phenothiazine derivative, was shown to possess its own analgesic activity comparable to that of morphine at a 3:2 dose relationship.In a double-blind crossover study of 18 patients suffering from chronic pain (cancer and arthritis), levomepromazine (15 mg.) was compared with morphine (10 mg.) and placebo. Three hours after intramuscular administration, levomepromazine proved to be significantly superior to placebo (p < .05) and indistinguishable from morphine. Evaluations of pain relief by estimations of changes in pain intensity were found to correlate well with evaluations based on recognition of pain relief exceeding 50%.The potent analgesic effect of levomepromazine was obtained at the price of excessive sedation. This, however, was considered an acceptable side effect in a patient suffering from chronic pain. These results provide encouragement in the quest for a non-addicting substitute for morphine.