What are the effects of a cyproheptadine (Periactin) overdose?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: March 25, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Cyproheptadine overdose is a medical emergency that requires immediate attention, and treatment typically involves supportive care, including monitoring vital signs and managing symptoms as they arise. The effects of a cyproheptadine overdose can be severe and potentially life-threatening, with symptoms including extreme drowsiness, confusion, dilated pupils, rapid heartbeat, flushing, hallucinations, seizures, and in severe cases, coma 1.

Symptoms and Treatment

The severity of overdose depends on the amount ingested, time since ingestion, and individual factors like age and health status. Healthcare providers will treat symptoms as they arise, which may include:

  • Managing anticholinergic effects
  • Controlling seizures with benzodiazepines
  • Providing respiratory support if needed
  • Administering activated charcoal if the ingestion was recent
  • Possibly gastric lavage

Important Considerations

Cyproheptadine is an antihistamine with anticholinergic properties that blocks histamine H1 receptors and serotonin receptors, which explains why overdose can cause both antihistamine and anticholinergic toxicity symptoms 1. Recovery usually occurs within 24-48 hours with proper medical care, though complications can arise in severe cases. It is essential to seek immediate medical attention if an overdose is suspected, and healthcare providers should be prepared to manage the potential complications of cyproheptadine overdose.

Key Points to Remember

  • Cyproheptadine overdose requires immediate medical attention
  • Treatment involves supportive care and managing symptoms as they arise
  • The severity of overdose depends on the amount ingested, time since ingestion, and individual factors
  • Recovery usually occurs within 24-48 hours with proper medical care, but complications can arise in severe cases 1

From the Research

Effects of Cyproheptadine Overdose

  • The effects of a cyproheptadine overdose can include anticholinergic symptoms such as delirium, agitation, disorientation, and hallucination 2.
  • In some cases, cyproheptadine overdose can result in choreoathetosis, a hyperkinesia likely caused by the anticholinergic properties of the drug 3.
  • Central anticholinergic syndrome can occur, characterized by psychosis, agitation, confusion, and hallucinations 4.
  • Symptoms of cyproheptadine overdose can also include sedative symptoms, with the majority of patients experiencing no or mild symptoms 2.
  • The time of symptom onset is typically less than 6 hours, and patients who remain asymptomatic 6 hours after exposure are unlikely to develop serious symptoms 2.

Clinical Presentation

  • Patients who ingest a significant amount of cyproheptadine are more prone to develop delirium 2.
  • Miotic pupils can be an unusual presentation in an acute cyproheptadine overdose 5.
  • In severe cases, cyproheptadine overdose can be fatal, especially when combined with other substances such as citalopram 6.

Management and Outcome

  • Supportive management is often sufficient for patients with cyproheptadine overdose, with all sequelae resolving within a few days 5.
  • Physostigmine can be used to treat delirious states caused by cyproheptadine overdose 3.
  • Patients who intentionally ingest cyproheptadine or cyproheptadine-containing sleeping pills may require hospitalization and monitoring for adverse effects 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Choreoathetosis induced by cyproheptadine.

Movement disorders : official journal of the Movement Disorder Society, 1989

Research

A fatality due to cyproheptadine and citalopram.

Journal of analytical toxicology, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.