A Case Report of Acute Anticholinergic Intoxication Following Intentional Cyproheptadine and Alcohol Overdose

Summary: This is a 45-year-old female patient who presented to the emergency department with altered mental status, pinpoint pupils, and tachycardia after intentionally ingesting a large quantity of the antihistamine cyproheptadine and alcohol. The patient was treated with physostigmine, a cholinesterase inhibitor, which improved her clinical condition. This case highlights the importance of recognizing and managing acute anticholinergic intoxication, a potentially life-threatening condition. Case Presentation: The patient, a 45-year-old female, was brought to the emergency department due to a poor response and the presence of “sleeping pills” (cyproheptadine 2 mg) and alcohol bottles. On arrival, she presented with confusion, decreased responsiveness, pupils dilated, and tachycardia. Physostigmine was administered for suspected anticholinergic intoxication. After physostigmine, the patient became more conscious, oriented, and alert, though still fatigued. She reported taking over 10 tablets of cyproheptadine and consuming alcohol due to insomnia, denying suicidal intent. Physical examination revealed the patient to be sleepy but oriented, with bilateral dilated pupils. Vital signs were notable for hypertension and tachycardia. Laboratory investigations, including arterial blood gas and electrocardiogram, were unremarkable. Based on the clinical presentation and history, the impression was acute anticholinergic intoxication. The patient was admitted for further management and monitoring. Anticholinergic intoxication can result from the overdose of various medications, including antihistamines. The administration of physostigmine helped to reverse the patient’s anticholinergic symptoms. Ongoing management in the observation unit was crucial to monitor for potential complications and address any mental health concerns.