Meperidine (patient information)
Street Names/Slangs: Demmies, Mapergan, Pethidine

# Why this medication is prescribed
Meperidine is used to relieve moderate to severe pain. Meperidine is in a class of medications called narcotic analgesics, a group of pain medications similar to morphine. It works by changing the way the body senses pain.

# How this medication should be used
Meperidine comes as a tablet and a syrup (liquid) to take by mouth. It is usually taken with or without food every 3-4 hours as needed for pain. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take meperidine exactly as directed.
Swallow the tablets whole; do not split, chew, or crush them. People who are dependent on meperidine or who want to abuse the medication may consider crushing, chewing, snorting, or injecting it. Meperidine may cause serious side effects or death if it is taken in these ways.
If you are taking meperidine syrup, mix your dose with half a glass of water and swallow the mixture. Swallowing undiluted meperidine syrup may numb the mouth.
Your doctor will probably adjust your dose of meperidine during your treatment. Be sure to tell your doctor about any pain and side effects you experience while taking this medication. This will help your doctor find the dose that is best for you.
Meperidine can be habit forming. Do not take a larger dose, or take it more often or for a longer period of time than you were told by your doctor. If you have taken meperidine for longer than a few weeks, do not stop taking the medication without talking to your doctor. Your doctor will probably decrease your dose gradually. If you suddenly stop taking meperidine, you may experience withdrawal symptoms. Withdrawal symptoms may include: restlessness, watery eyes, stuffy nose, yawning, sweating, chills, muscle pain, irritability, nervousness, stomach pain, upset stomach, vomiting, loss of appetite, diarrhea, fast breathing, fast heartbeat, and back pain.

# Other uses for this medicine
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

# Special precautions
Before taking meperidine:
- tell your doctor and pharmacist if you are allergic to meperidine or any other medications.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: acyclovir (Zovirax); antidepressants; butorphanol (Stadol NS); cimetidine (Tagamet); chlorpromazine (Thorazine); fluphenazine (Permitil, Prolixin); medications for anxiety, mental illness, pain, upset stomach, vomiting, and seizures; mesoridazine (Serentil); muscle relaxants such as baclofen (Lioresal), carisoprodol (Soma), cyclobenzaprine (Flexeril), methocarbamol (Robaxin), and tizanidine (Zanaflex); pentazocine (Talwin); perphenazine (Trilafon); phenytoin (Dilantin); prochlorperazine (Compazine); ritonavir (Norvir); sedatives; sleeping pills; thioridazine (Mellaril); trifluoperazine (Stelazine); triflupromazine (Vesprin); and tranquilizers. Also tell your doctor or pharmacist if you are taking the following medications or have stopped taking them within the past 2 weeks: monoamine oxidase (MAO) inhibitors including isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl), and tranylcypromine (Parnate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you use or have ever used street drugs, if you drink or have ever drunk large amounts of alcohol, and if you recently had surgery. Also tell your doctor if you have or have ever had Addison's disease (a condition in which the body does not produce certain important chemicals); a head injury or a problem with pressure in your head or brain; mental illness; asthma, chronic obstructive pulmonary disease (COPD), or other conditions that affect your breathing; sickle cell anemia (a blood disease); pheochromocytoma (a type of tumor); an abnormally curved spine, especially if it causes breathing problems; enlarged prostate; urethral stricture (narrowing of the opening through which urine leaves the body); irregular heartbeat; seizures; stomach problems; or thyroid, liver, kidney, or lung disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking meperidine, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking meperidine.
- you should know that meperidine may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
- ask your doctor about the safe use of alcoholic beverages while you are taking meperidine. *Alcohol and street drugs can make the side effects from meperidine worse and can cause serious harm or death.
- you should know that meperidine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking meperidine. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.

# Secial dietary instructions
Unless your doctor tells you otherwise, continue your normal diet.

# What to do if you forget a dose
This medication is usually taken as needed. If your doctor has told you to take meperidine regularly, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

# Side effects

## Minor side effects
Meperidine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- lightheadedness
- dizziness
- weakness
- headache
- extreme calm
- mood changes
- confusion
- agitation
- upset stomach
- vomiting
- stomach pain or cramps
- constipation
- dry mouth
- flushing
- sweating
- changes in vision

## Severe side effects
Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them or those listed in the IMPORTANT WARNING section, call your doctor immediately:
- slow or difficult breathing
- shaking hands that you cannot control
- muscle twitches or stiffening
- seizures
- hallucination (seeing things or hearing voices that do not exist)
- slow, fast, or pounding heartbeat
- difficulty urinating
- fainting
- rash
- hives
Meperidine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online  or by phone .

# Storage conditions needed for this medication
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Protect this medication from theft. Medication that is outdated or no longer needed should be flushed down the toilet, not thrown away. Talk to your pharmacist about the proper disposal of your medication.

# In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include:
- slowed breathing
- extreme sleepiness
- coma
- loose, floppy muscles
- cold, clammy skin
- slow heartbeat
- upset stomach
- blurred vision
- dizziness
- fainting

# Other information
Keep all appointments with your doctor.
Do not let anyone else take your medication. It is against the law to give this medication to anyone else. Ask your pharmacist any questions you have about refilling your prescription.

# Brand names
- Demerol Hydrochloride
- Demerol Hydrochloride Syrup

# Brand names of combination products
- Mepergan containing Meperidine Hydrochloride and Promethazine Hydrochloride
- Mepergan Fortis containing Meperidine Hydrochloride and Promethazine Hydrochloride

# Other names
- Isonipecaine
- Pethidine