SODIUM VALPROATE HAS A PROPHYLACTIC EFFECT IN MIGRAINE WITHOUT AURA -A TRIPLE-BLIND, PLACEBO-CONTROLLED CROSSOVER STUDY

We included 43 patients with migraine without aura in a triple-blind, placebo- and dose-controlled, crossover study of the prophylactic effe ct of slow-release sodium valproate; 34 patients completed the trial. The number of days with migraine was 3.5 per 4 weeks during treatment with sodium valproate and 6.1 during placebo (p 0.002). The severity a nd duration of the migraine attacks that did occur were not affected b y sodium valproate when compared with placebo. Fifty percent of the pa tients were responders, ie, their initial migraine frequency was reduc ed to 50% or less during sodium valproate as compared with 18% during placebo. The number of responders increased during the trial to 65% in the last 4 weeks of the active treatment period. There were no seriou s side effects requiring withdrawal of patients from the study. We con clude that sodium valproate is an effective and well-tolerated prophyl actic medication for migraine without aura.