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

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.

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.

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.

Our findings support the use of zonisamide as an alternative therapy for migraine prevention in patients with good response, but poor tolerance to topiramate.