Topiramate in essential tremor: Findings from double-blind, placebo-controlled, crossover trials

Objective: To evaluate topiramate in adults with essential tremor. Methods: This report represents the combined results of 3 randomized, double-blind, placebo-controlled, crossover trials that followed a common protocol. Study subjects were adults Q:18 years old) who had untreated or treated moderate to severe essential tremor involving upper extremities. Patients were randomized to a double-blind sequence of topiramate (400 mg/d or maximum tolerated dose) then placebo (n = 30) or placebo then topiramate (n = 32). A 2-week washout period separated 10-week double-blind treatment phases. Upper extremity tremor was assessed using the Fahn-Tolosa-Marin tremor rating scale (TRS). The primary efficacy measure was the TRS total score at the final visit for patients providing on-treatment data in both double-blind treatment periods. Secondary efficacy measures included change from baseline in TRS total score and in TRS subscale scores for tremor severity, motor task performance, and functional disability. Results: A total of 62 patients were enrolled. Total tremor score was significantly (P < 0.0001) lower with topiramate (28.7 +/- 1.0) vs placebo (37.0 +/- 1.0). The change from baseline in TRS total and subscale scores was significantly greater (P <= 0.005) with topiramate treatment (mean score reduction, 7.7-11.8 vs 0.08-2.0). Of the 28 patients who discontinued without completing both treatment periods, adverse events accounted for 13 of 18 discontinuations during topiramate treatment and 5 of 10 discontinuations during placebo exposure. Adverse events reported by 2 or more patients discontinuing topiramate were nausea (n = 3), paresthesia (n = 3), and concentration/attention difficulty (n = 2). Conclusions: Topiramate was associated with overall tremor reduction and improvements in tremor severity, motor task performance, and functional disability in patients with moderate to severe essential tremor.