Treatment of Acute Dystonic Reactions

Abstract

Acute dystonic reactions (ADRs) are unique symptoms which appear immediately following treatment with drugs that block dopamine receptors (DRBs). In the vast majority of cases, the responsible drugs are antipsychotics (APDs) of several types including phenothiazines, butyrophenones, and second-generation “atypical” APDs, as well as antiemetic agents such as metoclopramide and prochlorperazine. Acute dystonic reactions consist of intermittent or sustained muscular spasms and abnormal postures of the eyes, face, neck, throat, limbs, or trunk. Neck muscles are very commonly affected producing torticollis or retrocollis. In some cases subtle forms of orofacial dystonia occur without readily visible muscle spasm such as cramping sensations in the jaw, tongue, or throat with subjective difficulty chewing, swallowing, or speaking. Most individuals with ADRs present to the emergency room or in a psychiatric setting shortly after initiating treatment with an APD. Diagnosis requires familiarity with the disorder and its characteristic clinical features. Treatment requires immediate discontinuation of the offending drug and parenteral administration of an anticholinergic drug such as diphenhydramine or benztropine. The precise mechanism for this disorder is uncertain but relates to the effects of dopamine receptor blockade.