Mirtazapine in the treatment of essential tremor: an open-label, observer-blind study.

INTRODUCTION: Essential tremor (ET) is the most common movement disorder in the adult population. At present ET treatment shows limited efficacy, particularly in patients with severe and disabling symptoms. This study evaluates the clinical efficacy of mirtazapine in an untreated ET patient population.

MATERIALS AND METHODS: 30 ET patients (female/male = 19/11; average age = 71.4 +/- 8.3 years) were examined by clinical criteria, electromyographic (EMG), and apomorphine tests to study the cortical silent period. The patients were all treated with mirtazapine 30 mg daily.

RESULTS: Mirtazapine proved to be a good control agent for tremor symptomatology in 23/27 patients (85%) who completed 1 month of treatment, with a marked reduction of tremor; the benefit was maintained during the 12-month follow-up. No significant variation in EMG parameters was observed aside from two prevalent and distinct frequencies of tremors (5-6 Hz and 7-8 Hz) and a group of selected patients whose cortical silent period (SP) was markedly reduced. There were no clinical differences between the two subgroups. All apomorphine-tested patients showed an SP with no significant modifications.

CONCLUSIONS: Mirtazapine proved to be an efficacious drug treatment for tremor symptoms in patients suffering from ET. It had limited side effects and excellent overall tolerability, could be used as daily monotherapy, and did not interfere with any of the many other medications being taken simultaneously by the patients.