Cimetidine in the prophylaxis of migraine.

The prophylactic effect of the histamine H2-blocker cimetidine, either alone or combined with an H1-blocker (chlorpheniramine), was investigated in 34 migraine patients in a double-blind crossover trial. Twelve patients withdrew during the course of the trial, one because of the side effects and the remainder because of failure to attend checkups or to keep adequate record of attacks. In the 22 patients who completed the trial, there were no significant responses to cimetidine or cimetidine + chlorpheniramine, during 3 months' therapy, as compared with 3 months' therapy with placebo, either on number, duration or severity of attacks. The study demonstrates that cimetidine is unlikely to be effective in migraine, and casts doubt on the role of histamine in the development of migraine attacks.