Efficacy of levetiracetam in primary hemifacial spasm.

Hemifacial spasm (HFS) is a peripherally-induced movement disorder characterized by the involuntary, unilateral, intermittent, irregular, tonic or clonic contractions of muscles innervated by the ipsilateral facial nerve. Kindling-like hyperactivity of the facial nucleus induced by constant stimulation of compressing artery is considered as the predominant mechanism underlying the pathogenesis of HFS. As a treatment for HFS, microsurgical decompression and botulinum toxin injection have been shown to be highly successful. Anticonvulsant drugs relieve HFS in some patients; however, the use of such drugs is limited owing to their side effects, predominantly in elderly patients. We experienced two elderly HFS patients who exhibited a marked response to levetiracetam (LEV) without side effects. Although the exact underlying pharmacological mechanism remains unknown, we assume anti-kindling effect as one of the important pharmacological mechanism underlying the effect of LEV against HFS. Moreover, LEV is considered to be suitable for use in elderly patients because of its good tolerability. In addition, the lack of hepatic induction or inhibition makes it an easy and safe drug when used in addition to other anticonvulsants. Although the long-term benefit remains unknown, LEV may represent an alternative treatment for elderly HFS patients who are unable to undergo or decline surgical intervention and/or botulinum toxin injections or are intolerant to other anticonvulsants.