Rabbit syndrome as a side effect triggered by amisulpride

Abstract

Extrapyramidal system (EPS) side‐effects are known to appear in association with long‐term use of antipsychotics. “Rabbit syndrome (RS),” first described in 1972, is a rare EPS side‐effect of antipsychotic drugs (Villeneuve, 1972). Rhythmical and regular motions of the jaw and lip occur in the vertical plane in the perioral region at a frequency of approximately 5 Hz. Absence of movement in the tongue is a differentiating characteristic. Amisulpride is an atypical antipsychotic. In contrast to other members of this group, it is a selective D2 andD3 receptor antagonist. It is used in low doses in supportive pharmacotherapy in the treatment of obsessive compulsive disorder (OCD) and of psychosis. Because of its selective binding to dopaminergic receptors, side‐effects of amisulpride are rare. Our review of the literature revealed a single previous case of RS developing with amisulpride use. We describe a case started on amisulpride with a diagnosis of OCD and in which rabbit syndrome developed on the 18th day of treatment.