Neuroleptic Malignant Syndrome Due to Donepezil

Case Report

Manuel Monti, Francesco Paciul

Abstract

Neuroleptic Malignant Syndrome (NMS) first described nearly five decades ago, is an idiosyncratic, life-threatening complication of treatment with drugs that is characterized by fever, sever e muscle rigidity, and autonomic and mental status changes. There are many different drugs that can cause NMS. Most of the drugs are antipsychotic drugs. NMS can also develop when dopaminergic drugs are suddenly withdrawn, but there are also other drugs that don't belong to any of the above categories. An old male patient was admitted to our Emergency Department for intermittent fever with onset from three days. His medications included amlodipine, oral steroid, and donepezil, which was administered at the dose of 10 mg/day. At the time of admission the patient showed stupor without other relevant signs at the physical exam. Infectious diseases and systemic diseases were ruled out during the course. Patient experienced during the following ten hours after the admission a further worsening of the fever to a stable level of 42°. At the neurological exam appeared diffuse severe muscular stiffness and bilateral fixed miose. A lumbar puncture was also performed that was negative. He died a few hours later. An autopsy was also organized that did not show the reported results. Based on the findings in our patient and from the data from literature, we hypothesize that the patient developed a NMS due to Donepezil. This indicates that when we are faced with a patient with altered mental state, fever, muscle stiffness and/or autonomous instability, an accurate medical history is required and we must consider Donepezil as a potential cause of suspected NMS. 

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