Meperidine, available as hydrochloride salt, is a narcotic analgesic, a classification term used to describe medications capable of producing a reversible depression of the central nervous system for pain control. Because of its potential for physical and psychological dependence, meperidine is a carefully controlled substance. It is commonly referred to by one of its brand names, Demerol.
There are several possible indications for the administration of meperidine. It is commonly used for the relief of moderate to severe pain, particularly in obstetrics. Meperidine is also widely used preoperatively, and as an adjunct to anesthesia during surgery. Meperidine is not recommended for long-term management of chronic pain, such as pain caused by cancer, because of its potential for psychological and physical dependence.
Meperidine is a synthetic compound that acts as an agonist—meaning it attaches to opioid receptors in the central nervous system and stimulates physiologic activity normally stimulated by naturally occurring substances such as endorphins (short for endogenous morphine). Meperidine acts much like morphine, although constipation, suppression of the cough reflex, and smooth muscle spasm are all reduced with meperidine.
Meperidine is available in a banana-flavored syrup, in a tablet, and in a liquid form for injection. Oral meperidine tends to be less effective than the injectable form. When taking the syrup, patients should dilute it with approximately one half glass of water to reduce temporary anesthesia to the mouth and tongue.
The recommended dosage of meperidine depends on the purpose for which it is prescribed, as well as the population in whom it is administered. For example, elderly patients, or patients with underlying medical problems that increase side effects or decrease drug metabolism, should generally be given reduced dosages. Meperidine can be taken orally, in tablet or syrup form, intravenously (directly into a vein), or by injection into the muscle (intramuscularly) or connective tissue (subcutaneously).
Generally, repeated doses administered to manage pain should be given by injection intramuscularly. The subcutaneous route is acceptable for occasional administration. When given intravenously, meperidine should be diluted and administered very slowly. When taken in conjunction with phenothiazine or other tranquilizers, the dose should be decreased by as much as a half. Specific dosages are as follows.
FOR RELIEF OF MODERATE TO SEVERE PAIN.
The recommended dosage for adults for pain relief is 50-150 mg every three to four hours by oral or intramuscular route. When given intravenously through a patient-controlled analgesia (PCA) device, an initial dose of 10 mg should be administered. The PCA should be programmed to administer between 1-5 mg every 6-10 minutes. If meperidine is given continuously through an intravenous line, the dose should be adjusted based on patient response to a range of 15-35 mg an hour. Children should be given 1-1.8 mg per kg (2.2 pounds) intramuscularly or subcutaneously.
FOR PREOPERATIVE MEDICATION.
Adults may be given 50-100 mg of meperidine intramuscularly, or subcutaneously 30-90 minutes prior to surgery. Children's dosages should be reduced to 1-2 mg per kg through the same routes.
For obstetric pain control. The recommended dosage for control of regular (not sporadic) pain in this setting is 50-100 mg every 1-3 hours intramuscularly or subcutaneously.
Other patients who should avoid meperidine use include those with previous hypersensitivity to narcotics, or those with underlying respiratory problems. Meperidine, even in recommended therapeutic doses, can decrease the respiratory drive. Conditions such as asthma or chronic obstructive pulmonary disease may increase the likelihood of respiratory difficulty. Meperidine can also impair judgment, and should not be used in individuals engaging in activities that require alertness, such as driving.
Because its effects on a fetus are unknown, meperidine is not recommended in pre-labor stage pregnant women. Even in labor, when it may be indicated for pain control, meperidine may cause respiratory depression of the mother and her baby, particularly premature babies. Meperidine is excreted in breast milk, and, if needed, should be administered several hours before breastfeeding to minimize ingestion by the infant.
The most common adverse effects of meperidine are lightheadedness, dizziness, sedation, nausea and/or vomiting, and sweating. Less common, but more severe, side effects include respiratory depression and abnormally low blood pressure.
Individuals who are taking, or who have recently taken, drugs called monoamine oxidase (MAO) inhibitors (a class of antidepressants), should not be given meperidine. Reactions have been reported in this population that are characterized by a variety of signs and symptoms including respiratory distress, coma, abnormally low or abnormally high blood pressure, hyperexcitability, and even death. If administration of a narcotic is required, it should be given in small, gradually increasing test doses under careful supervision.
Adverse effects such as respiratory depression and decreased blood pressure are more common when meperidine is administered in conjunction with other narcotic analgesics, anesthetics, phenothiazines, sedatives, or any other type of drug that suppresses the central nervous system. Alcohol should also be avoided.
Tamara Brown, R.N.
—A drug that binds to cell receptors and stimulates activities normally stimulated by naturally occurring substances.
—A classification of medications that relieves pain by temporarily depressing the central nervous system.
—A drug that possesses some properties characteristic of opiate narcotics but not derived from opium.
Patient controlled analgesic (PCA)
—A device resembling an intravenous pump that allows patients to self-medicate within pre-established dosage parameters for pain control.