Definition

Promethazine is a medicine used to treat nausea and vomiting. Promethazine overdose occurs when someone takes too much of this medicine. It is in a class of drugs called phenothiazines, which were developed to treat psychiatric disturbances.

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 center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.

Alternative Names

Phenergan overdose

Poisonous Ingredient

Promethazine

Symptoms

Bladder and kidneys:

• Urinary hesitancy
• Inability to urinate

Heart and blood vessels:

• Rapid heartbeat
• Weakness from low blood pressure

Nervous system:

• Drowsiness or coma (lack of responsiveness)
• Agitation, nervousness, confusion, excitation, disorientation, hallucinations
• Depression
• Fever
• Unsteadiness
• Restlessness, including inability to sit still and involuntary repetitive movements
• Seizures
• Tremor (unintentional trembling)

Other:

• Dry mouth
• Flushed skin
• Involuntary tongue movement
• Large (dilated) pupils with vision difficulty
• Muscle stiffness and spasms in face or neck

Before Calling Emergency

The following information is helpful for emergency assistance:

• The person's age, weight, and condition
• Name of product (as well as the ingredients and strength, if known)
• The time it was swallowed
• The amount swallowed
• If the medicine was prescribed for the person

However, DO NOT delay calling for help if this information is not immediately available.

Poison Control

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 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 pill container with you to the hospital, if possible.

What to Expect at the Emergency Room

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 as appropriate. The person may receive:

• Airway support, including oxygen, breathing tube through the mouth (intubation),and ventilator (breathing machine)
• Blood and urine tests
• Chest x-ray
• CT (computerized axial tomography) scan
  
• ECG (electrocardiogram, or heart tracing)
• Fluids through the vein (intravenous or IV)
• Laxative
• Medicines to treat symptoms

Outlook (Prognosis)

If the person survives the first 24 hours, recovery is likely. People who experience heart rhythm irregularities and seizures are at highest risk for a serious outcome. Few people actually die from promethazine overdose.

References

Aronson JK. Promethazine. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:972-973.

Gault A. Approach to the poisoned patient. In: Cameron P, Little M, Mitra B, Deasy C, eds. Textbook of Adult Emergency Medicine. 5th ed. Philadelphia, PA: Elsevier Ltd. 2020:chap 25.1.

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.