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 < .001). We observed a significant reduction in headache severity and disability, as assessed by visual analog scale and migraine disability assessment scale. Finally, when compared with the 1-month period prior to starting zonisamide, a reduced use of analgesics was recorded at the end of the follow-up. Conclusion.- Our findings support the use of zonisamide as an alternative therapy for migraine prevention in patients with good response, but poor tolerance to topiramate.