Chlorpromazine overdose

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
• Drooling
• Dry mouth
• Sores on the gums, tongue, or in the throat
• Stuffy nose
• Yellow eyes

HEART AND BLOOD

• High or very low blood pressure
• Pounding heartbeat
• 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

NERVOUS SYSTEM

• Agitation, irritability, confusion
  
• Convulsions (seizures)
  
• Disorientation, coma (lack of responsiveness)
  
• Drowsiness
• Fever
• Low body temperature
• Restlessness linked with repeated foot shuffling, rocking, or pacing (akathisia)
  
• Tremor, motor tics that the person cannot control (dystonia) 
  
• Uncoordinated movement, slow movement, or shuffling (with long-term use or overuse) 
• Weakness

REPRODUCTIVE SYSTEM

• Change in female menstrual pattern

SKIN

• Bluish skin color
• Hot skin
• Rash

STOMACH AND INTESTINES

• Constipation
• Loss of appetite
• Nausea

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.

Have this information ready:

• The 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.

Take the container with you to the hospital, if possible.

Your health care provider will measure and monitor you vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated.

Tests that may be done include:

• Blood and urine tests
• Chest x-ray
• CT scan (advanced brain imaging)
• Electrocardiogram (ECG)

Treatment may include:

• Activated charcoal
• Breathing support, including oxygen, tube through the mouth into the lungs, and breathing machine (ventilator)
• Fluids through a vein (IV)
• Laxative
• 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.

Monas J, Skolnik AB. Antipsychotics. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 150.

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.