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Trade/other name(s): Demerol, Mepergan

Why would this drug be used?

Meperidine is used to treat short-term pain. It usually works for moderate to severe pain.

How does this drug work?

Meperidine is a widely used man-made (synthetic) opioid analgesic and works in the same way as morphine. It binds to opioid receptors in the brain and central nervous system (CNS), which reduces both the perception of and emotional response to pain.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), sickle cell anemia, low thyroid, Addison's disease (low adrenal function), pheochromocytoma (kidney tumor), or heart disease. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have atrial fibrillation, atrial flutter, or irregular heartbeat. Meperidine can raise your heart rate to dangerous speeds.
  • If you have trouble passing urine, narrow urethra, or if you have an enlarged prostate. Meperidine can make it harder to urinate.
  • If you have ever had a seizure, head injury, or if you have had problems with pressure or a tumor in your head or brain. Meperidine can raise your risk of seizures.
  • If you have asthma, emphysema, chronic bronchitis, sleep apnea, or other breathing problem, you should not take meperidine. It can make breathing problems worse.
  • If you have taken monoamine oxidase inhibitors within the past 2 weeks (see "Interactions with other drugs", below). Meperidine can cause coma, slow or shallow breathing, low blood pressure, excitability, seizures, or shock.
  • If you have low blood pressure. Meperidine can worsen this.
  • If your kidneys or liver are damaged or do not work well.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy.
  • If you are breast-feeding. The drug passes into breast milk and may harm the baby.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

The following drugs can cause meperidine or its breakdown products to build up in the body and cause more serious complications:

  • Acyclovir (Zovirax, an antiviral drug)
  • Cimetidine (Tagamet, a blocker of stomach acid)
  • Ritonavir (Norvir, used for HIV treatment)

The anti-seizure drug phenytoin can lower the level of meperidine in the body, but raise the level of the substance the body breaks it down into (see "Precautions", below), called normeperidine. This can cause confusion, excitability, seizures, and other complications.

Other medicines that slow down the brain or nervous system, such as these, can cause worse side effects if taken with meperidine:

  • Anti-anxiety drugs (tranquilizers or sedatives)
  • Sleeping pills
  • Muscle relaxers
  • Barbiturates
  • Anti-seizure medicines
  • Other opioid drugs
  • Anesthetics (tell the doctor before surgery if you have been taking meperidine)
  • Antidepressants such as amitriptyline, desipramine, doxepin, imipramine, nortriptyline
  • Anti-psychotic drugs
  • Certain anti-nausea medicines
  • Alcohol

Some of these can cause slowed breathing, low blood pressure, extreme sleepiness, coma, or even death if taken with meperidine.

Antidepressants of the older MAO inhibitor type such as phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), or selegiline (Emsam) may cause coma, slow or shallow breathing, a drop in blood pressure, excitability, high body temperature, diarrhea, seizures, or shock if meperidine is given within 2 weeks of the last MAO inhibitor dose.

Buprenorphine (Subutex, Suboxone), butorphanol (Stadol), nalbuphine (Nubain), or pentazocine (Talwin, Talacen) may decrease the effects of meperidine or stop its action altogether. This can cause withdrawal if you have taken meperidine for some time.

Check with your doctor, nurse, or pharmacist about whether other medicines, vitamins, herbs, and supplements can cause problems with this medicine.

Interactions with foods

No serious interactions with foods other than alcohol are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Meperidine can be given in different ways: by an injection in a vein (IV), into a muscle (intramuscular injection), or under the skin (subcutaneous injection). You can also take meperidine as a pill or syrup by mouth. When taking the syrup form, dilute it in at least half a glass of water to avoid affecting the mouth and throat.

Your dose is based on the reason the medicine is being given and how well it treats your pain. Take this drug exactly as prescribed by your doctor. If you have any questions or do not understand the instructions, talk to your doctor or nurse.

If you are taking the medicine at home, store it in a tightly closed container and away from children, pets, and others who may take the drug. Do not share your medicine with others. Flush unused medicine down the toilet.


Meperidine is used to relieve short term pain and is not recommended for long term use, such as for managing cancer pain. The body breaks down meperidine into normeperidine, which builds up with repeat doses. This substance may cause confusion, delirium, and seizures. Older patients and those with other serious medical problems are more likely to have these side effects. If these problems develop, call your doctor right away.

Since meperidine affects the central nervous system (CNS), do not take other drugs or substances that slow down the brain and nervous system, such as alcohol, sedatives, and sleeping pills, unless your doctor tells you to do so. This can lead to overdoses.

This medicine can cause drowsiness and lightheadedness. Do not drive, operate machinery, or perform other activities that require alertness until you know how you react to this medicine. If you feel dizzy, it may help to lie down.

Meperidine can make you feel dizzy or faint, and increase your risk of falling. Be careful getting up, changing position, or walking. Start slowly and hold onto something or someone to keep you steady. If you feel lightheaded or dizzy, it may help to lie down. It is best to have a responsible adult with you for the first few days after starting the meperidine and after any increase in dose, until you know how you will respond to it.

Call your doctor right away if you have trouble breathing, get short of breath, feel very drowsy, or start seeing or hearing things that aren't there. These may be signs your dose is too high, or you could have gotten an accidental overdose of the medicine.

Tell your doctor or nurse right away if you have trouble passing your urine, trouble walking, vision problems, fainting, trouble swallowing, or other problems.

If you are having any kind of surgery or medical procedure, be sure to tell the doctor or dentist in charge that you are using this medicine.

Your doctor may suggest that you take acetaminophen or aspirin to boost the pain relief of meperidine. It is important to find out if any of your other medicines contain either of these drugs. They are in many remedies and it is easy to accidentally get too much of them. Check with your doctor, nurse, or pharmacist to find out which of these drugs are included in your daily medicines.

Constipation is a very common side effect of taking opioid pain medicines. While you're taking meperidine, you should take medicines such as stool softeners, bulk-forming agents, and/or laxatives as needed to have regular (daily) bowel movements. Talk to your nurse or doctor about this when you first start this medicine. Drink plenty of fluids throughout the day, and try to eat foods high in fiber such as whole grains, bran, fruits, and vegetables. If you have not moved your bowels in 2 days, call your doctor or nurse immediately.

Talk to your doctor or nurse about using the smallest effective dose to reduce side effects and the development of tolerance and physical dependence. Tolerance means that larger doses needed to give the same effect. Physical dependence means that the body goes into withdrawal if drug is suddenly stopped. Both of these develop normally when strong (opioid) medicines are taken over several weeks to treat chronic pain. But tolerance and physical dependence aren't the same as addiction, which starts when the drug is taken for pleasure rather than pain relief. Tell your doctor or nurse if you still have pain even though you are taking the medicine as prescribed. Do not adjust your dose without talking to your doctor or nurse first.

If you have been taking meperidine regularly for more than a few days, it's important that you gradually taper down your dose when you're ready to stop. Do not stop taking this drug without talking to your doctor or nurse. Suddenly stopping meperidine can cause withdrawal symptoms such as anxiety, restlessness, runny nose, teary eyes, yawning, dizziness, sweating, chills, nausea, vomiting, aches, cramps, and tiredness.

Meperidine is used to relieve short term pain, such as that due to surgery, rather than chronic pain, such as that related to cancer. The pain relief doesn't last long, and frequent use can lead to seizures and other dangerous side effects.

This drug is a controlled substance, and may be habit forming. Do not allow others to take your medicine. A person who has taken opioid pain medicines for a long time often needs large doses for pain relief, while the same amount could quickly kill someone else.

If you think you or someone else may have taken an overdose, get emergency help right away. Symptoms of overdose may include confusion, severe nervousness or restlessness, extreme dizziness, severe weakness, extreme drowsiness, slow heart beat, slow or irregular breathing, or seizures.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Constipation*
  • Drowsiness*
  • Sedation (feeling sleepy or tired)*
  • Nausea
  • Vomiting
  • Dizziness, lightheadedness*
  • Dry mouth
  • Sweating

Less common

  • Changes in mood, such as euphoria (happiness), irritability, or agitation
  • Mental clouding or confusion*
  • Slow or shallow breathing
  • Low blood pressure, especially when sitting up or standing up*
  • Slowed digestion
  • Slow heart rate


  • Trouble urinating
  • Tremor
  • Twitching or jerking movements
  • Seizures*
  • Hallucinations (seeing, feeling, or hearing things that aren't there)
  • Decreased sexual interest
  • Impotence
  • Serious allergic reaction with itching, skin welts, rash, swelling in the mouth or throat, trouble breathing, or other symptoms
  • Death due to breathing problems, low blood pressure, overdose, interactions with other drugs or alcohol, allergic reaction, or other effects

*See "Precautions" section for more detailed information.

There are some other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984.)

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 11/28/2011
Last Revised: 11/28/2011