Pharmacological prophylaxis of chronic migraine: a review of double-blind placebo-controlled trials.

Chronic migraine is an important public health problem. The aim of treatment should be to reduce migraine frequency and its negative impact on functioning, as well as to limit the use of acute medications. These goals may be accomplished by introducing effective prophylaxis. The aim of the present article is to critically review the published evidence on the pharmacological prophylaxis of chronic migraine, analysing published double-blind, placebo-controlled studies on adult patients. The results of the review indicate that tizanidine, gabapentin, valproic acid, and particularly topiramate are effective prophylactics against chronic migraine, with improvements in several endpoints that were significantly superior to those achieved by placebo. However, the different results found by different trials, as well as several methodological problems inherent in the trials, suggest the need for further research to provide clear indications from large, multicentre, controlled trials with homogeneous inclusion criteria and adequate endpoints.