Meperidine

Pain Relief

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

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

Symptoms of an allergic reaction include: rash, hives, itching, chills, fever, headache, muscle ache, shortness of breath, coughing, tightness in the throat, swelling of the face or neck.

Not all patients who take meperidine will experience these side effects. Common side effects are bolded, but there may be others. Please report all suspected side effects to your doctor or pharmacist.

Find more information on side effects.

Possible late effects

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.

Tips for patients and families

Be sure to discuss all questions and instructions with your doctor or pharmacist.

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.

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Always check the medication label. Many medicines look the same. Do not take any new medicine, including over-the counter medicines or supplements, without checking with your doctor or pharmacist. Talk to your doctor or pharmacist about what to do in the case of a missed dose, allergic reaction, or medical emergency.

This information is not intended to be a complete guide and is not a substitute for talking with your provider. Medicine names, appearance, formulas, or availability may vary by clinic location. Always follow the instructions given by your care team.

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Reviewed: June 2024