RESUMO
Chronic migraine (CM) is a disabling condition with not many treatment strategies available. Topiramate is effective in episodic migraine prevention, however little is known about its effect in CM. An open label study was performed. Sixty-four patients diagnosed with CM or probable CM according to the IHS diagnostic criteria were enrolled, 50 patients were available for analysis and an intention-to-treat methodology was applied. The primary endpoint considered was the number of patients with a decrease in headache frequency higher than 50%. The median dose was 100 mg, a reduction in frequency higher than 50% occurred in 33 patients (66%) and 14 (28%) presented a complete response, defined as a frequency reduction higher than 95%. The medication was well tolerated. The most common side effects found were weight loss, paraesthesias, nausea, cognitive dysfunction, fatigue, somnolence, insomnia and depression. Our findings suggest that topiramate is effective in CM prophylaxis.