Cyproheptadine is a type of drug called an antihistamine. These drugs are used to relieve allergy symptoms. Cyproheptadine overdose occurs when someone takes more than the normal or recommended amount of this medicine. This can be by accident or on purpose.
This article is for information only. DO NOT use it to treat or manage an actual overdose. If you or someone you are with has an overdose, call the local emergency number (such as 911), or the local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.
Cyproheptadine can be harmful in large amounts.
Cyproheptadine is an allergy medicine.
Below are symptoms of a cyproheptadine overdose in different parts of the body.
BLADDER AND KIDNEYS
- Inability to urinate
- Difficulty urinating
EYES, EARS, NOSE, MOUTH, AND THROAT
- Blurred vision
- Dilated (wide) pupils
- Dry mouth
- Ringing in the ears (tinnitus)
HEART AND BLOOD VESSELS
- Rapid heartbeat
- Increased blood pressure
- Coma (lack of responsiveness)
- Convulsions (seizures)
- Delirium (acute confusion)
- Disorientation, hallucinations
- Irregular or rapid heartbeat
- Tremor (shaking)
- Unsteadiness, weakness
- Flushed and dry skin
STOMACH AND INTESTINES
- Nausea and vomiting
Before Calling Emergency
Have this information ready:
- Person's age, weight, and condition
- Name of product (ingredients and strength, if known)
- Time it was swallowed
- Amount swallowed
- If the medicine was prescribed for the person
Your local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline will let you talk to experts in poisoning. They will give you further instructions.
This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.
What to Expect at the Emergency Room
Take the container to the hospital with you, if possible.
The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure.
Tests that may be done include:
- Blood and urine tests
- Chest x-ray
- ECG (electrocardiogram, or heart tracing)
Treatment may include:
- Activated charcoal
- Fluids through a vein (by IV)
- Medicine to treat symptoms
- Breathing support, including a tube through the mouth and into the lungs and connected to a breathing machine (ventilator)
If the person survives the first 24 hours, survival is likely. Few people actually die from an antihistamine overdose. Very high doses of antihistamines can cause serious heart rhythm disturbances, which may result in death.
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Monte AA, Hoppe JA. Anticholinergics. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 145.
Review Date 7/20/2021
Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.