Generic name: Meperidine hydrochloride.

Other brand names: Pethadol, Pheperidine Hydrochloride.

Demerol is a narcotic analgesic. It works by altering the response to painful stimuli. 

Quick Facts About Demerol


Used to treat moderate to severe pain.

Demerol Dosage

Take exactly as prescribed. If using syrup form, take with a half glass of water.

  • Usual adult dose: 50 to 150 milligrams every 3 or 4 hours. Seniors: doctor may reduce dosage.
  • Usual child dose: 0.5 to 0.8 milligram per pound of body weight, every 3 or 4 hours.
  • Missed dose: take as soon as possible, unless almost time for next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Demerol Side Effects

Overdose symptoms:

bluish discoloration of the skin, cold and clammy skin, coma or extreme sleepiness, limp and/or weak muscles, low blood pressure, slow heartbeat, troubled or slowed breathing. Severe overdose may result in breathing stoppage, heart attack, or death. If you suspect an overdose, immediately seek medical attention.

More common side effects: dizziness, light-headed-ness, nausea, sedation, sweating, vomiting.

Less common or rare Demerol side effects: agitation, constipation, difficulty urinating, disorientation, dry mouth, fainting, fast heartbeat, feeling of elation or depression, flushing of the face, hallucinations, headache, hives, impairment of physical performance, itching, low blood pressure, mental sluggishness or clouding, palpitations, rashes, restlessness, severe convulsions, slow heartbeat, tremors, troubled and slowed breathing, uncoordinated muscle movements, visual disturbances, weakness.


Do not take with MAO inhibitors such as Nardil or Parnate.

Inform your doctor before combining Demerol with:

anti depressants such as Elavil and Tofranil; antihistamines such as Benadryl; cimetidine (Tagamet); major tranquilizers such as Mellaril and Thorazine; other narcotic painkillers such as Percocet and Tylenol with Codeine; phenytoin (Dilantin); sedatives such as Halcion and Restoril; tranquilizers such as Xanax and Valium.

Do not drink alcohol while taking Demerol; slows brain activity and intensifies the effects of alcohol. 

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Demerol appears in breast milk; could affect a nursing infant.

Doctor may reduce dosage for seniors.

Follow doctor’s instructions carefully for children.

  • May impair your ability to drive a car or operate machinery. May also cause dizziness or light-headedness. Do not take part in any activity that requires alertness.
  • Should not take if sensitive to, or had an allergic reaction to Demerol or other narcotic painkillers.
  • Monitor for mental and physical tolerance if you take Demerol on an ongoing basis, or if you have had a drug abuse problem.
  • Use with extreme caution if you have a severe asthma attack, if you have recurring lung disease, if unable to inhale or exhale extra air when needed.
  • Use with caution if you have: Addison’s disease, an enlarged prostate, convulsions, head injury, irregular heartbeat, severe abdominal condition, severe liver or kidney disorder, underactive thyroid gland, or urethral stricture.
  • Notify your doctor that you are taking Demerol before having surgery.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Demerol side effects, please contact your healthcare provider.