Pethidine Injection BP (Meperidine HCl)



Meperidine HCl

Opioid Analgesic

Action And Clinical Pharmacology: Meperidine is a narcotic analgesic with multiple actions qualitatively similar to those of morphine. The most prominent of these actions involve the CNS and organs which are composed of smooth muscle. Analgesia and sedation are the principal actions of therapeutic value.

Some evidence suggests that meperidine may produce less smooth muscle spasm, constipation, and depression of the cough reflex than equivalent analgesic doses of morphine. Meperidine parenteral doses of 80 to 100 mg is approximately equivalent in analgesic effect to 10 mg of morphine. Its onset of action is slightly more rapid than with morphine, and there is a slightly shorter duration of action. Meperidine is significantly less effective by the oral rather than parenteral route. However, the exact ratio of oral to parenteral effectiveness is unknown.

Indications And Clinical Uses: The relief of moderate to severe pain involved in many medical, surgical, obstetrical and dental situations.

Contra-Indications: Hypersensitivity to meperidine. Contraindicated in patients who are currently receiving or who have been receiving MAO inhibitors within 14 days. The mechanism of these reactions is unclear, but may be related to a pre-existing hyperphenylalaninemia. Some have resembled the syndrome of acute narcotic overdose characterized by coma, severe respiratory depression, cyanosis and hypotension. In other reactions, hyperexcitability, convulsions, tachycardia, hyperpyrexia and hypertension have been the predominant manifestations. Although it is unknown if other narcotics are exempt from the risk of such reactions, virtually all the reported reactions have occurred with meperidine. A sensitivity test should be performed if a narcotic is needed in such patients. The sensitivity test should involve repeated, small, incremental doses of morphine administered over the course of several hours. The patient’s condition and vital signs should be under careful observation throughout the test. Severe reactions have been treated with i.v. hydrocortisone or prednisolone with the addition of i.v. chlorpromazine in those cases exhibiting hypertension and hyperpyrexia. The usefulness and safety of narcotic antagonists in the treatment of these reactions is unknown. There is a chemical incompatibility between solutions of meperidine and barbiturates.

Manufacturers’ Warnings In Clinical States: Drug Dependence: Meperidine can produce drug dependence similar to that of morphine and therefore has the potential for being abused. Psychic and physical dependence, as well as tolerance may develop upon repeated administration of meperidine. Meperidine should therefore be prescribed and administered with the same degree of caution appropriate to the use of morphine. As with other narcotics, meperidine is subject to the provisions of the Narcotic Control Act.

Drug Interactions: Interaction With Other CNS Depressants: In the case of patients who are concurrently receiving other narcotic analgesics, general anesthetics, phenothiazines, other tranquilizers (see Dosage), sedative-hypnotics (including barbiturates), tricyclic antidepressants, and other CNS depressants (including alcohol), meperidine should be used with great caution and in reduced dosage. The following conditions may result: respiratory depression, hypotension, and profound sedation or coma.

Head Injury and Increased Intracranial Pressure: Head injury, other intracranial lesions, or a pre-existing increase of intracranial pressure may markedly exaggerate the respiratory depressant effects of meperidine and its capacity to elevate cerebrospinal fluid pressure. Furthermore, adverse reactions produced by narcotics may obscure the clinical course of patients with head injuries. Meperidine must be used with extreme caution and only if its use is deemed essential in such patients.

I.V.: If necessary, meperidine may be given i.v., but the injection should be given very slowly, preferably in the form of diluted solution. Increased incidence of adverse reaction such as severe respiratory depression, apnea, hypotension, peripheral circulatory collapse, and cardiac arrest have occurred with rapid i.v. injection of narcotic analgesics, including meperidine. Meperidine should not be administered i.v. without the immediate availability of a narcotic antagonist and the facilities for assisted or controlled respiration. The patients should be lying down when meperidine is given parenterally, especially i.v.

Asthma and Other Respiratory Conditions: Meperidine should be used with extreme caution in the following patients who are: having an acute asthmatic attack, have chronic obstructive pulmonary disease or cor pulmonale, have a substantially decreased respiratory reserve, and have pre-existing respiratory depression, hypoxia, or hypercapnia. Even usual therapeutic doses of narcotics may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea in such patients.

Hypotensive Effect: Severe hypotension in the postoperative patient or any individual whose ability to maintain blood pressure has already been compromised by a depleted blood volume or the administration of drugs such as the phenothiazines or certain anesthetics may result from the administration of meperidine.

Occupational Hazards: Ambulatory Patients: The mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery may be impaired by meperidine. The patient should be cautioned accordingly. Like other narcotics, meperidine may produce orthostatic hypotension in ambulatory patients.

Pregnancy: Meperidine should not be used in pregnant women prior to the labor period, unless the potential benefits outweigh the possible hazards. Safe use in pregnancy prior to labor has not been established relative to possible adverse effects on fetal development. Therefore when meperidine is used as an obstetrical analgesic, it crosses the placental barrier and respiratory depression or psychophysiologic functions can be produced in the newborn; resuscitation may be required (see Overdose: Symptoms and Treatment).

Lactation: Meperidine appears in the milk of nursing mothers given the drug.

Precautions: Supraventricular Tachycardias: Meperidine should be used with caution in patients with atrial flutter and other supraventricular tachycardias due to possible vagolytic action. This action may produce a significant increase in the ventricular response rate.

Convulsions: Meperidine may aggravate pre-existing convulsions in patients with convulsive disorders. Convulsions may occur in individuals without a history of convulsive disorders if dosage is escalated substantially above recommended levels because of tolerance development.

Acute Abdominal Conditions: In the case of patients with acute abdominal conditions, the administration of meperidine or other narcotics may obscure the diagnosis or clinical course.

Special Risk Patients: Elderly or debilitated patients, and those with severe impairment of hepatic or renal function, hypothyroidism, Addison’s disease and prostatic hypertrophy or urethral stricture should be given meperidine with caution and the initial dose should be reduced.

Incompatibilities: Solutions of meperidine are chemically incompatible with aminophylline, barbiturates, heparin, iodines, methiallin, phenytoin, sodium bicarbonate, sulfadiazine and sulfisoxazole.

Adverse Reactions: As with other narcotic analgesics, the major hazards of meperidine are respiratory depression and, to a lesser degree, circulatory depression; respiratory arrest, shock, and cardiac arrest have occurred. Lightheadedness, dizziness, sedation, nausea, vomiting, and sweating are among the most frequently observed adverse reactions. These effects seem to be more prominent in ambulatory patients and in those who are not experiencing severe pain. Lower doses are advisable in such individuals. Some adverse reactions in ambulatory patients may be alleviated if the patient lies down.

Other adverse reactions include: CNS: euphoria, dysphoria, weakness, headache, agitation, tremor, severe convulsions, uncoordinated muscle movements, transient hallucinations and disorientation and visual disturbances. Inadvertent injection about a nerve trunk may result in sensory-motor paralysis which is usually, though not always, transitory.

Gastrointestinal: dry mouth, constipation, biliary tract spasm.

Cardiovascular: flushing of the face, tachycardia, bradycardia, palpitation, hypotension (see Warnings), syncope and phlebitis following i.v. injection.

Genitourinary: urinary retention.

Allergic: pruritus, urticaria, other skin rashes, wheal and flare over the vein with i.v. injection.

Others: pain at injection site; local tissue irritation and induration following s.c. injection, particularly when repeated; antidiuretic effect.

Symptoms And Treatment Of Overdose: 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 i.v. route, apnea, circulatory collapse, cardiac arrest, and death may occur.

Treatment: In parenteral overdosage, circulation should be maintained with infusions of plasma or suitable electrolyte solution and assisted respiration may be necessary. If consciousness is impaired and respiratory depressed, an opioid antagonist should be administered. Naloxone, a pure antagonist, is now the treatment of choice. Administer i.v. naloxone (e.g., 0.4 mg) which may be repeated at 2- to 3-minute intervals. For children, the initial dose recommended is 0.01 mg/kg of naloxone. In neonates, a more rapid and improved antagonism was noted after 0.02 mg/kg was administered. A response should be seen after 2 or 3 doses. Note the duration of action of naloxone is usually shorter than that of meperidine and thus the patient should be carefully observed for signs of CNS depression returning.

Note: In a individual physically dependent on opioids, the administration of the usual dose of an opioid 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 opioid antagonists in such individuals should be avoided if possible. If an opioid antagonist must be used to treat serious respiratory depression in the physically dependent patient, the antagonist should be administered with extreme care and only 10 to 20% of the usual initial dose administered.

Dosage And Administration: Pain Relief: If i.v. administration is required, dosage should be adjusted for the patient and made with repeated slow i.v. injections of fractional doses (e.g., 10 mg/mL) with the use of an infusion pump. When administered concomitantly with phenothiazines and tranquilizers, meperidine dose should be reduced.

Preoperative Medication: Repeated slow i.v. injections of fractional doses (e.g., 10 mg/mL) via an infusion pump.

Support of Anesthesia: Repeated slow i.v. injections of fractional doses (e.g., 10 mg/mL) with the use of an infusion pump or continuous i.v. infusion of a more dilute solution (e.g., 1 mg/mL) should be used and titrated to patient needs and operative procedure.

Availability And Storage: Each mL of sterile solution contains: meperidine HCl 10 mg. Nonmedicinal ingredients: sodium chloride and water for injection. Preservative-free. Rapiject prefilled, single-dose syringes of 50 mL. Store between 15 and 25°C, protected from light.

PETHIDINE INJECTION BP Faulding Meperidine HCl Opioid Analgesic

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