Zonisamide for migraine prophylaxis in topiramate-intolerant patients: An observational study

Background.- Zonisamide, a sulfonamide analog, is an antiepileptic drug with mechanisms of action similar to topiramate. Because of its pharmacodynamic and pharmacokinetics profiles, zonisamide is also potentially suitable for migraine prevention. Methods.- Tolerability and effectiveness of zonisamide for migraine prophylaxis in patients with a good response to topiramate, but interrupting it for intolerable side effects, were evaluated in 34 patients. After a 1-month period of wash-out, patients were treated with zonisamide (up to a 100 mg/day dosage) for 6 consecutive months. Results.- Zonisamide was well tolerated, only 4 (12%) patients reported transient and tolerable side effects. Mean number of days with headache per month was reduced from 14.9 ± 5.3 during the wash-out period to 2.5 ± 0.6 after 6 months of zonisamide (P