[Zonisamide in refractory essential tremor]

Abstract

Introduction: Essential tremor is one of the most frequent movement disorders. It is characterized by postural and action tremor that may affect different regions of the body. Among current treatments propranolol and primidone are included. However, these two drugs have demonstrated a limited efficacy and several adverse events. Additionally, they are contraindicated in patients with cardiac insufficiency and several respiratory diseases. New antiepileptic drugs are revealing as a possibility in the treatment of this disease. AIM. To evaluate efficacy and tolerability of zonisamide in the treatment of essential tremor.

Patients and methods: We perform a retrospective study about 13 patients with essential tremor refractory to an average of 2.8 drugs. Age, sex, zonisamide dosage, adverse events, duration and response to the treatment before and after the treatment were collected and analysed. Average zonisamide dosage was 215 mg/day and average duration of the treatment was 121 days.

Results: Nine of 13 patients included in our study experienced a good response. A positive response was understood as a decrease on the limitation of daily activities and an improvement on neurological examination. Zonisamide was well tolerated and no patient abandoned the study for this reason.

Conclusions: Our data suggest that zonisamide is effective and well tolerated in the treatment of essential tremor. Placebo-controlled and bigger studies are warranted to confirm these results.