Neuroleptic malignant syndrome induced by donepezil in a patient treated with risperidone and trazodone

Area of Science:

• Pharmacology
• Neurology
• Geriatrics

Background:

• Neuroleptic malignant syndrome (NMS) is a rare, life-threatening adverse drug reaction primarily linked to antipsychotic medications.
• Donepezil, an acetylcholinesterase inhibitor used for Alzheimer's disease, has been implicated in NMS infrequently.
• Concurrent use of antipsychotics and acetylcholinesterase inhibitors may increase the risk of NMS.

Purpose of the Study:

• To report a rare case of NMS in an elderly patient initiated on donepezil.
• To investigate the potential role of donepezil in precipitating NMS, alone or in combination with other psychotropic drugs.

Main Methods:

• Case report of an elderly male patient presenting with symptoms suggestive of NMS.
• Review of the patient's medication history, including recent initiation and dose escalation of donepezil.
• Clinical assessment, laboratory investigations (including creatine kinase levels), and response to treatment.

Main Results:

• The patient developed classic NMS symptoms (fever, muscle rigidity, altered mental status) following donepezil initiation and dose increase.
• Elevated creatine kinase levels confirmed muscle breakdown consistent with NMS.
• The patient recovered promptly after discontinuation of donepezil and supportive care; NMS did not recur upon reintroduction of prior antipsychotic and antidepressant medications.

Conclusions:

• Donepezil can induce neuroleptic malignant syndrome, even in elderly patients with pre-existing psychiatric conditions.
• This case underscores the importance of considering donepezil as a potential trigger for NMS, particularly when co-administered with antipsychotics.
• Clinicians should maintain a high index of suspicion for NMS in patients starting or adjusting donepezil therapy.