Drug-induced dystonia

Abstract

Drug-induced dystonia (DID) is a rarely diagnosed adverse reaction to a sufficiently large number of drugs. Acute DID (ADID) occurs soon after starting to take a drug or raising its dose, and switching from one antipsychotic medication to another, especially to its injectable dosage form. Tardive DID (TDID) develops a few months or years after starting drug intake or 3 months after stopping therapy. The diagnosis of TDID is based on the persistence of dystonic hyperkinesis for more than 1 month, the use of a dopamine receptor blocking agent, and the absence of other causes of its development. The risk factors for DID are male sex; young age (less than 30 years of age); a history of dystonic reactions; hypocalcemia, alcohol use while taking the drug. DID is most commonly related to therapy with antipsychotics, metoclopramide, antidepressants, and antiepileptic drugs. The short-term use of anticholinergic drugs (benzotropin, diphenhydramine) is effective in treating ADID. Anticholinergic drugs and atypical antipsychotics (clozapine, quetiapine), benzodi-azepines, muscle relaxants (baclofen), and dopamine reuptake inhibitors (tetrabenazine) are used to treat TDID. To prevent DID, it is very important that a physician should be aware of that this unwanted adverse reaction may occur and that a drug with the lowest risk for DID should be chosen.