A case of SUNCT syndrome responsive to zonisamide.

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a rare headache syndrome that represents a subtype of trigeminal autonomic cephalalgia thought to be highly refractory to treatment. More recently, numerous anticonvulsant agents including lamotrigine, topiramate, gabapentin, and carbamazepine have been reported to be partially or completely effective for treating SUNCT. We report the case of a patient with SUNCT in whom symptoms were completely relieved with carbamazepine at 600 mg/day. However, carbamazepine had to be discontinued due to severe rash. Zonisamide was selected for continued treatment, as a Na-channel blocker like carbamazepine but with lower risk of producing skin rashes as caused by carbamazepine. Attacks ceased completely with 300 mg/day of zonisamide achieving a blood serum level of 19 µg/ml. This is the first case report to describe zonisamide alone completely eliminating SUNCT symptoms. Zonisamide should be considered a viable candidate drug for the treatment of SUNCT.