Antipsychotic-Induced Oromandibular Dystonia in Multiple Sclerosis Successfully Treated with Clozapine: A Case Report

Abstract

Multiple Sclerosis (MS) is a chronic, inflammatory, and demyelinating autoimmune disease of the central nervous system, and while various neurological symptoms may follow a primary relapse, primary extrapyramidal symptoms remain rare. Psychiatric comorbidities frequently accompany MS; however, if psychotropic medications are not utilized with appropriate indications or dosages, they may induce extrapyramidal side effects, complicating diagnosis and treatment management. In this report, we discuss a 45-year-old female patient with MS and Generalized Anxiety Disorder who developed oromandibular dystonia (OMD) and akathisia following the concurrent initiation of olanzapine, aripiprazole, and paroxetine. Clinical and radiological evaluations ruled out an acute MS relapse, and the OMD was attributed to a pharmacokinetic interaction (CYP2D6 inhibition) and drug-induced effects, as confirmed by a score of 7 on the Naranjo Adverse Drug Reaction Probability Scale. Following the failure of standard anticholinergic treatments, the patient achieved full symptomatic remission with low-dose clozapine titration. This case underscores that psychotropic medications must be prescribed with extreme caution in patients with neurodegenerative conditions, and clozapine should be considered an effective treatment option for refractory drug-induced OMD.