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What is promethazine?

Promethazine (also called Phenergan®) is used to treat nausea and vomiting. Promethazine is available in these forms:

  • 12.5 mg, 25 mg, and 50 mg tablets taken by mouth
  • 1.25 mg/ml and 5 mg/ml syrup (liquid) taken by mouth
  • 12.5 mg, 25 mg, and 50 mg suppositories inserted into the rectum
  • 50 mg/ml liquid given by vein

How to take and store promethazine

  • Your doctor will tell you how much promethazine to take and how often to take it.
  • Syrup and tablets
    • You may take the tablets or syrup with food or milk to avoid an upset stomach.
    • Store the tablets and syrup at room temperature. Store them away from light, heat, and moisture.
  • Rectal suppositories
    • Never take suppositories by mouth. Insert the suppository into the rectum after removing the wrapper.
    • You may wet the rectum with water to make it easier to insert the suppository. Do not apply any petroleum jelly (Vaseline®) to the rectum before you insert the suppository.
    • Place the pointed end of the suppository into the rectum, and push gently until it is all the way inside.
    • Wash your hands with soap and water after you have inserted the suppository.
    • Store the suppositories in a tightly closed container in the refrigerator.

Possible side effects of promethazine

  • Feeling drowsy
  • Dry mouth or throat

Call the doctor right away if you have any of these severe side effects:

  • Trouble breathing
  • Fast, slow, or irregular heart beat
  • Skin rash, itching, or hives
  • Convulsions
  • Uncontrolled movements of the eyes, neck, or tongue

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call the doctor, nurse, or pharmacist at 595-3300. If you are outside the Memphis area, dial toll-free 1-866-2STJUDE (1-866-278-5833), and press 0 once the call is connected.

Special instructions for promethazine

  • Stop taking promethazine if you have a severe side effect (listed above).
  • Do not take promethazine if you have had an allergic reaction to any of these medicines:
    • Prochlorperazine (Compazine®)
    • Chlorpromazine (Thorazine®)
    • Thioridazine (Mellaril®)
  • Because promethazine may cause you to feel drowsy, you should not drive, operate machinery, or perform any hazardous activity until you see how your body responds to this medicine.
  • This medicine can increase the risk of falls.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

ATTENTION: If you speak another language, assistance services, free of charge, are available to you. Call 1-866-278-5833 (TTY: 1-901-595-1040).

ATENCIÓN: si habla español, tiene a su disposición servicios gratuitos de asistencia lingüística. Llame al 1-866-278-5833 (TTY: 1-901-595-1040).

تنبيه: إذا كنت تتحدث باللغة العربية فيمكنك الاستعانة بخدمات المساعدة اللغوية المتوفرة لك مجانا. .يرجى الاتصال بالرقم. 5833-278-866-1  (الهاتف النصي: 1040-595-901-1).