Neuroleptic malignant syndrome (NMS) is a rare but potentially fatal complication of treatment with antipsychotic drugs. Clinical features of NMS are muscle rigidity, hyperpyrexia, autonomic instability, mental status changes, and high level of creatine phosphokinase. Primidone is an antiepileptic drug and also used for the treatment of essential tremor. It may interact with many drugs such as antipsychotics. This report presents a 49-year-old patient who developed NMS following the abrupt discontinuation of primidone.
