Effect of zonisamide on essential tremor: a pilot crossover study in comparison with arotinolol.

We performed a pilot, crossover trial of zonisamide (ZNS) on essential tremor patients. Patients were randomly selected to start either ZNS or arotinolol treatment for 2 weeks. After a washout period, the patients were switched to an alternative drug. The assessment of tremor was carried out using the Fahn-Tolosa-Marin's clinical rating scale for tremor at baseline and 2 weeks after administration of each drug. There was a significant improvement after ZNS and arotinolol administration compared with the baseline. There was no significant difference in the antitremor effect between ZNS and arotinolol; however, ZNS was more effective for tremors of cranial nerve areas. Although the number of enrolled patients was limited in the present study, this open-label pilot study suggests that ZNS may have a therapeutic potential for essential tremor. A controlled trial of this drug in the future would be valuable.