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What is meperidine?

Meperidine (Demerol®) is an opioid pain medicine. Meperidine is also given by vein (IV) to control “chills” that some patients get when they are receiving amphotericin B (a medicine given IV to treat fungal infections). Meperidine is available as a 50-mg white tablet and as a clear liquid taken by mouth. Meperidine is also available as a clear liquid given by vein (IV).

Possible side effects of meperidine


  • Feeling drowsy
  • Nausea
  • Slower than normal rates of breathing
  • Low blood pressure

Later (usually more than a day after treatment starts)

  • Constipation
  • Itching and hives
  • Drowsy feeling; sedation
  • Feeling dizzy or fainting
  • Nausea and vomiting
  • Mood changes (feeling sadder or happier than usual)
  • Dry mouth
  • Problems urinating
  • Increased risk of seizures

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 meperidine

  • If you have any of the side effects listed on page 1, most should decrease after you have taken meperidine for a couple of days. Tell your doctor if the side effects increase while you are taking this medicine. It may mean you need less meperidine.
  • If you are taking this medicine regularly, do not stop taking it until the doctor tells you to do so. Stopping meperidine without slowly decreasing the dose can lead to diarrhea, headache, sweating, muscle cramps, trouble sleeping, nausea, vomiting, and feeling restless. These symptoms usually do not occur if meperidine is only given before or during an amphotericin B dose.
  • This medicine may cause you to feel dizzy or drowsy. Meperidine may impair your ability to drive a car or operate heavy machinery. Do not take part in these activities if you are sleepy, drowsy, dizzy, or not alert after taking meperidine.
  • If you have not slept because of your pain, when you start this medicine you may sleep more for the first few days to “catch up” on missed sleep.
  • If you are taking this medicine regularly, then you should increase your fluid and fiber intake to help prevent constipation. Tell your doctor or nurse if you have not had a bowel movement in 3 to 5 days. You may need to take a stool softener or laxative to relieve your constipation.
  • If you have taken meperidine for a long time, your doctor may slowly decrease your dose to wean you off meperidine. During this time, watch for a sudden onset of diarrhea, headache, sweating, muscle cramps, trouble sleeping, nausea, vomiting, or feeling restless. If these symptoms occurs, call your doctor right away. It could mean your dose is being decreased too fast.
  • Other medicines can increase the drowsy feeling caused by meperidine. These medicines include:
    • Alcohol (found in many over-the-counter cough and cold medicines)
    • Diphenhydramine (over-the-counter Benadryl®)
    • Promethazine
    • Diazepam and lorazepam
    • Antidepressants (such as amitriptyline)
    • Medicines used to treat seizures (such as carbamazepine, phenytoin, gabapentin, phenobarbital, and valproic acid).
  • Always tell your doctor if you are taking any of these medicines or if you start taking any new medicine while you are taking meperidine.


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).