Meperidine
Demerol
Meperidine hydrochloride is an opioid analgesic indicated for the relief of moderate to severe pain. It has multiple actions qualitatively similar to those of morphine; the most prominent of these involve the central nervous system and organs composed of smooth muscle. The principal actions of therapeutic value are analgesia and sedation. There is some evidence which suggests that meperidine may produce less smooth muscle spasm, constipation, and depression of the cough reflex than equianalgesic doses of morphine.
How supplied
Available in the following strengths: 100mg/ml; 10mg/ml; 25mg/ml; 50mg/ml
Meperidine, in 60 mg to 80 mg parenteral doses, is approximately equivalent in analgesic effect to 10 mg of morphine. The onset of action is slightly more rapid than with morphine, and the duration of action is slightly shorter. In clinical practice, opioids are usually combined with a benzodiazepine for endoscopic sedation.
Meperidine Dosing for Endoscopic Sedation
Adult - Initial dose: 25-50 mg
- Additional doses: doses of 25 mg can be administered every 2-5 minutes until adequate sedation is achieved
- Onset of action: 3-6 minutes
- Peak effect: 6-7 minutes
- Duration of effect: 60-180 minutes
Pediatric - Initial dose (<50kg): 1mg/kg
- Additional doses: 1mg/kg can be administered every 2-4 minutes to max dose of 3mg/kg
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Symptoms
Serious overdosage with meperidine is characterized by respiratory depression (a decrease in respiratory rate and/or tidal volume, Cheyne-Stokes respiration, cyanosis), extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, and sometimes bradycardia and hypotension. In severe overdosage, particularly by the intravenous route, apnea, circulatory collapse, cardiac arrest, and death may occur.
Treatment
Primary attention should be given to the reestablishment of adequate respiratory function through provision of a patent airway and institution of assisted or controlled ventilation. The opioid antagonist, naloxone hydrochloride, is a specific antidote against respiratory depression which may result from overdosage or unusual sensitivity to opioids, including meperidine. Therefore, an appropriate dose of this antagonist should be administered, preferably by the intravenous route, simultaneously with efforts at respiratory resuscitation An antagonist should not be administered in the absence of clinically significant respiratory or cardiovascular depression. Oxygen, intravenous fluids, vasopressors, and other supportive measures should be employed as indicated.
NOTE: In an individual physically dependent on narcotics, the administration of the usual dose of a narcotic antagonist will precipitate an acute withdrawal syndrome. The severity of this syndrome will depend on the degree of physical dependence and the dose of antagonist administered. The use of narcotic antagonists in such individuals should be avoided if possible. If a narcotic antagonist must be used to treat serious respiratory depression in the physically dependent patient, the antagonist should be administered with extreme care and only one-fifth to one-tenth the usual initial dose administered.
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Naloxone hydrochloride
Meperidine should be given with caution and the initial dose should be reduced in certain patients such as the elderly or debilitated, and those with severe impairment of hepatic or renal function, sickle cell anemia, hypothyroidism, Addison’s disease, pheochromocytoma and prostatic hypertrophy or urethral stricture. In patients with pheochromocytoma, meperidine has been reported to provoke hypertension.
- Use in Pediatric Patients: Meperidine’s half-life in children may be as long as 3 to 4 hours.
- Use in Hepatically Impaired Patients: Accumulation of meperidine and/or its active metabolite, normeperidine, can occur in patients with hepatic impairment. Meperidine should therefore be used with caution in patients with hepatic impairment.
- Use in Renally Impaired Patients: Accumulation of meperidine and/or its active metabolite, normeperidine, can also occur in patients with renal impairment. Meperidine should therefore be used with caution in patients with renal impairment.
- Carcinogenesis, mutagenesis, impairment of fertility: Studies to assess the carcinogenic or mutagenic potential of meperidine have not been conducted. Studies to determine the effect of meperidine on fertility have not been conducted.
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- Drug Abuse and Dependence: Meperidine can produce drug dependence of the morphine type and therefore has the potential for being abused. Psychic dependence, physical dependence, and tolerance may develop upon repeated administration of meperidine, and it should be prescribed and administered with the same degree of caution appropriate to the use of morphine.
- Controlled Substance: Meperidine is classified as a Schedule C-II controlled substance by federal regulation. (see DEA Controlled Substance Schedules) Like other narcotics, meperidine is subject to the provisions of the federal narcotic laws.
- Head Injury and Increased Intracranial Pressure: The respiratory depressant effects of meperidine and its capacity to elevate cerebrospinal fluid pressure may be markedly exaggerated in the presence of head injury, other intracranial lesions, or a preexisting increase in intracranial pressure. Furthermore, narcotics produce adverse reactions which may obscure the clinical course of patients with head injuries. In such patients, meperidine must be used with extreme caution and only if its use is deemed essential.
- Asthma and Other Respiratory Conditions: Meperidine should be used with extreme caution in patients having an acute asthmatic attack, patients with chronic obstructive pulmonary disease or cor pulmonale, patients having a substantially decreased respiratory reserve, and patients with preexisting respiratory depression, hypoxia, or hypercapnia. In such patients, even usual therapeutic doses of narcotics may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea.
- Hypotensive Effect: The administration of meperidine may result in severe hypotension in the postoperative patient or any individual whose ability to maintain blood pressure has been compromised by a depleted blood volume or the administration of drugs such as the phenothiazines or certain anesthetics.
- Use in Ambulatory Patients: Meperidine may impair the mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. The patient should be cautioned accordingly. Meperidine, like other narcotics, may produce orthostatic hypotension in ambulatory patients.
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The major hazards of meperidine, as with other narcotic analgesics, are respiratory repression and, to a lesser degree, circulatory depression; respiratory arrest, shock, and cardiac arrest have occurred. The most frequently observed adverse reactions include lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. These effects seem to be more prominent in ambulatory patients and in those who are not experiencing severe pain. In such individuals, lower doses are advisable. Some adverse reactions in ambulatory patients may be alleviated if the patient lies down. Other adverse reactions include:
- Nervous System: Euphoria, dysphoria, weakness, headache, agitation, tremor, uncoordinated muscle movements (e.g., muscle twitches, myoclonus), severe convulsions, transient hallucinations and disorientation, visual disturbances.
- Gastrointestinal: Dry mouth, constipation, biliary tract spasm.
- Cardiovascular. Flushing of the face, tachycardia, bradycardia, palpitation, hypotension (see WARNINGS), syncope.
- Genitourinary: Urinary retention.
- Allergic: Pruritus, urticaria, other skin rashes, wheal and flare over the vein with intravenous injection.
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Meperidine should be used with great caution and in reduced dosage in patients who are concurrently receiving other narcotic analgesics, general anesthetics, phenothiazines, other tranquilizers sedative-hypnotics (including barbiturates), tricyclic antidepressants monoamine oxidase (MAO) inhibitors and other CNS depressants (including alcohol). Respiratory depression, hypotension, and profound sedation or coma may result.
Fentanyl
Meperidine is contraindicated in patients who are receiving monoamine oxidase (MAO) inhibitors or those who have recently received such agents. Therapeutic doses of meperidine have occasionally precipitated unpredictable, severe, and occasionally fatal reactions in patients who have received such agents within 14 days. The mechanism of these reactions is unclear, but may be related to a preexisting hyperphenylalaninemia. Some have been characterized by coma, severe respiratory depression, cyanosis, and hypotension, and have resembled the syndrome of acute narcotic overdose. In other reactions the predominant manifestations have been hyperexcitability, convulsions, tachycardia, hyperpyrexia, and hypertension. Although it is not known that other narcotics are free of the risk of such reactions, virtually all of the reported reactions have occurred with meperidine. If a narcotic is needed in such patients, a sensitivity test should be performed in which repeated, small, incremental doses of morphine are administered over the course of several hours while the patient's condition and vital signs are under careful observation. (Intravenous hydrocortisone or prednisolone has been used to treat severe reactions, with the addition of intravenous chlorpromazine in those cases exhibiting hypertension and hyperpyrexia. The usefulness and safety of narcotic antagonists in the treatment of these reactions is unknown.)
SourcesCohen LB, DeLegge MH, Aisenberg J, Brill JV, Inadomi JM, et al.
AGA Institute review of endoscopic sedation. Gastroenterology. 2007 Aug;133(2):675-701.
Demerol Meperidine Hydrocholoride, USP [package insert]. Sanofi-Synthelabo Inc. Revised 2003.
http://www.fda.gov/medwatch/SAFETY/2003/03May_PI/Demerol_PI.pdf Accessed February 18, 2008.
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