Epidemiology, risk factors, and treatment of chronic migraine: a focus on topiramate.

The term chronic daily headache refers to a heterogeneous group of headache disorders characterized by a frequency of headaches on > or = 15 days per month. Chronic migraine is a subtype of chronic daily headache. The prevalence of chronic migraine is approximately 1%. Baseline attack frequency and acute medication overuse have been identified as potential risk factors for the progression of migraine from an episodic disorder to a chronic condition. There is an unmet patient need for effective and safe treatments for patients with chronic migraine, but data from rigorous controlled trials are limited. Previous studies have demonstrated that topiramate is an effective and safe preventive treatment for episodic migraine. In addition, pilot studies have suggested the utility of topiramate for the prevention of chronic migraine. Two randomized, double-blind, placebo-controlled, multicenter trials investigating the efficacy and safety of topiramate in the treatment of patients with chronic migraine have recently been completed. This review presents comparative data from these 2 clinical trials, which suggest that topiramate at a dose of 100 mg daily is effective and generally well tolerated in chronic migraine.