Anticonvulsants in Migraine Prophylaxis

Abstract

Anticonvulsants have mechanisms of action that may be effective for the prevention of migraine attacks. The results of two multicenter, randomized, double-blind, placebo-controlled trials established the effectiveness of divalproex in the prophylactic treatment of migraine headache. The first trial showed a mean 4-week headache rate during the treatment phase of 3.5 in the divalproex group compared with 5.7 in the placebo group (p < 0.001). In the second study, the 4-week migraine headache rate was 2.8, 2.7, and 3.0 (500 mg, 1000 mg, and 1500 mg, respectively) compared with 5.6 in the placebo group. Of the 202 patients exposed to divalproex during the two trials, 17% discontinued because of adverse events, compared with 5% of the patients receiving placebo. Gabapentin was evaluated in a randomized, placebo-controlled, double-masked study. Forty-six percent of patients experienced a 50% or greater reduction in the 4-week headache rate, compared with 16% of patients taking placebo. Sixteen percent of patients in the gabapentin group and 9% of patients in the placebo group discontinued because of adverse events. In a randomized, placebo-controlled, double-masked study, topiramate was associated with significantly greater reduction in 28-day migraine frequency than was placebo (1.83 vs 0.55 attacks, respectively; p = 0.0015). Eleven percent of patients receiving topiramate withdrew from the study because of adverse events. In a second study, a significantly greater proportion of patients achieved at least a 50% reduction in migraine frequency with topiramate than with placebo (46.7% vs 6.7%, respectively; p = 0.035). Among topiramate-treated patients, 27% discontinued because of adverse events.