Toxic Myopathy due to Antidopaminergic Medication Without Neuroleptic Malignant Syndrome

Severe recurrent proximal muscle weakness without neuroleptic malignant syndrome secondary to antidopaminergic medication has rarely been reported. We report a 29-year-old man with history of obsessive compulsive disorder and Tourette syndrome who presented with 2 months of worsening dyspnea 3 weeks after starting ziprasidone 40 mg daily that required mechanical ventilation. A year before, after an increased risperidone dose from 0.5 to 1 mg daily, he had developed proximal muscle weakness that spontaneously improved 2 months after discontinuation of risperidone. On this admission, his creatine kinase (CK) was 3318 units/L, and ziprasidone was discontinued. He fully recovered 2 months after discontinuation of ziprasidone, and his CK was 62 units/L. Genetic testing for limb-girdle muscular dystrophy was negative. This case highlights the importance of evaluating CK level in patients taking antidopaminergic medication with any suggestion of muscle weakness to prevent potentially life-threatening complication.