Chlorpromazine is a prescription medicine used to treat psychotic disorders. It may also be used to prevent nausea and vomiting, and for other reasons.
This medicine may also change the metabolism and the effect of other drugs.
Chlorpromazine 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 overdoses, 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.
Chlorpromazine can be poisonous in large amounts.
Chlorpromazine is found in chlorpromazine hydrochloride.
Other medicines may also contain chlorpromazine.
Below are symptoms of a chlorpromazine overdose in different parts of the body.
AIRWAYS AND LUNGS
- No breathing
- Rapid breathing
- Shallow breathing
BLADDER AND KIDNEYS
- Inability to urinate
- Weak urine stream
EYES, EARS, NOSE, MOUTH, AND THROAT
- Blurred vision
- Difficulty swallowing
- Dry mouth
- Sores on the gums, tongue, or in the throat
- Stuffy nose
- Yellow eyes
HEART AND BLOOD
- High or very low blood pressure
- Rapid, irregular heartbeat
MUSCLES, BONES AND JOINTS
- Muscle spasms
- Rapid, involuntary movements of the face (chewing, blinking, grimaces, and tongue movements)
- Stiff muscles in the neck or back
- Drowsiness, coma
- Confusion, hallucinations (rare)
- Inability to sit still
- Low body temperature
- Weakness, uncoordinated movements
- Change in female menstrual pattern
- Bluish skin color
- Hot skin
STOMACH AND INTESTINES
- Loss of appetite
Seek medical help right away. DO NOT make a person throw up unless poison control or a health care provider tells you to do so.
Before Calling Emergency
Have this information ready:
- Person's age, weight, and condition
- The name of the medicine and strength, if known
- When it was swallowed
- The amount swallowed
- If the medicine was prescribed for the person
Your local control poison 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 with you to the hospital, if possible.
The health care provider will measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated. The person may receive:
- Breathing support, including oxygen and a tube through the mouth into the lungs and breathing machine (ventilator)
- Blood and urine tests
- Chest x-ray
- CT scan (computerized axial tomography or advanced brain imaging)
- ECG (electrocardiogram, or heart tracing)
- Intravenous fluids (through a vein)
- Medicine to reverse the effects of the drug and treat symptoms
Chlorpromazine is fairly safe. Most likely, an overdose will only cause drowsiness and some side effects such as uncontrolled movements of the lips, eyes, head, and neck for a short time. These movements may continue if they are not treated quickly and correctly.
In rare cases, an overdose can cause more serious symptoms. Nervous system symptoms may be permanent. The most serious side effects are usually due to damage to the heart. If heart damage can be stabilized, recovery is likely. Life threatening heart rhythm disturbances may be difficult to treat, and may result in death. Survival past 2 days is usually a good sign.
Aronson JK. Chlorpromazine. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:274-275.
Skolnik AB, Monas J. Antipsychotics. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 155.
Last reviewed on: 7/20/2021
Reviewed 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.