Methergine® (methylergonovine maleate) Tablets, USP Rx only

Methergine^® (methylergonovine maleate) acts directly on the smooth muscle of the uterus and increases the tone, rate, and amplitude of rhythmic contractions. Thus, it induces a rapid and sustained tetanic uterotonic effect which shortens the third stage of labor and reduces blood loss. The onset of action after I.V. administration is immediate; after I.M. administration, 2-5 minutes, and after oral administration, 5-10 minutes.

      Pharmacokinetic studies following an I.V. injection have shown that methylergonovine is rapidly distributed from plasma to peripheral tissues within 2-3 minutes or less. The bioavailability after oral administration was reported to be about 60% with no accumulation after repeated doses. During delivery, with intramuscular injection, bioavailability increased to 78%. Ergot alkaloids are mostly eliminated by hepatic metabolism and excretion, and the decrease in bioavailability following oral administration is probably a result of first-pass metabolism in the liver.

      Bioavailability studies conducted in fasting healthy female volunteers have shown that oral absorption of a 0.2 mg methylergonovine tablet was fairly rapid with a mean peak plasma concentration of 3243 ± 1308 pg/mL observed at 1.12 ± 0.82 hours. For a 0.2 mg intramuscular injection, a mean peak plasma concentration of 5918 ± 1952 pg/mL was observed at 0.41 ± 0.21 hours. The extent of absorption of the tablet, based upon methylergonovine plasma concentrations, was found to be equivalent to that of the I.M. solution given orally, and the extent of oral absorption of the I.M. solution was proportional to the dose following administration of 0.1, 0.2, and 0.4 mg. When given intramuscularly, the extent of absorption of Methergine solution was about 25% greater than the tablet. The volume of distribution (Vd_ss/F) of methylergonovine was calculated to be 56.1 ± 17.0 liters, and the plasma clearance (CLp/F) was calculated to be 14.4 ± 4.5 liters per hour. The plasma level decline was biphasic with a mean elimination half-life of 3.39 hours (range 1.5 to 12.7 hours). A delayed gastrointestinal absorption (T_max about 3 hours) of Methergine tablet might be observed in postpartum women during continuous treatment with this oxytocic agent.

Hypertension; toxemia; pregnancy; and hypersensitivity.

This drug should not be administered I.V. routinely because of the possibility of inducing sudden hypertensive and cerebrovascular accidents. If I.V. administration is considered essential as a lifesaving measure, Methergine^® (methylergonovine maleate) should be given slowly over a period of no less than 60 seconds with careful monitoring of blood pressure. Intra-arterial or periarterial injection should be strictly avoided.

Caution should be exercised in the presence of sepsis, obliterative vascular disease, hepatic or renal involvement. Also use with caution during the second stage of labor. The necessity for manual removal of a retained placenta should occur only rarely with proper technique and adequate allowance of time for its spontaneous separation.

The most common adverse reaction is hypertension associated in several cases with seizure and/or headache. Hypotension has also been reported. Nausea and vomiting have occurred occasionally. Rarely observed reactions have included: acute myocardial infarction, transient chest pains, arterial spasm (coronary and peripheral), bradycardia, tachycardia, dyspnea, hematuria, thrombophlebitis, water intoxication, hallucinations, leg cramps, dizziness, tinnitus, nasal congestion, diarrhea, diaphoresis, palpitation, rash, and foul taste.¹

      There have been rare isolated reports of anaphylaxis, without a proven causal relationship to the drug product.

Methergine^® (methylergonovine maleate) has not been associated with drug abuse or dependence of either a physical or psychological nature.

Symptoms of acute overdose may include: nausea, vomiting, abdominal pain, numbness, tingling of the extremities, rise in blood pressure, in severe cases followed by hypotension, respiratory depression, hypothermia, convulsions, and coma.

      Because reports of overdosage with Methergine^® (methylergonovine maleate) are infrequent, the lethal dose in humans has not been established. The oral LD₅₀ (in mg/kg) for the mouse is 187, the rat 93, and the rabbit 4.5.² Several cases of accidental Methergine injection in newborn infants have been reported, and in such cases 0.2 mg represents an overdose of great magnitude. However, recovery occurred in all but one case following a period of respiratory depression, hypothermia, hypertonicity with jerking movements, and, in one case, a single convulsion.

      Also, several children 1-3 years of age have accidentally ingested up to 10 tablets (2 mg) with no apparent ill effects. A postpartum patient took 4 tablets at one time in error and reported paresthesias and clamminess as her only symptoms.

      Treatment of acute overdosage is symptomatic and includes the usual procedures of:

1. removal of offending drug by inducing emesis, gastric lavage, catharsis, and supportive diuresis.
   
2. maintenance of adequate pulmonary ventilation, especially if convulsions or coma develop.
   
3. correction of hypotension with pressor drugs as needed.
   
4. control of convulsions with standard anticonvulsant agents.
   
5. control of peripheral vasospasm with warmth to the extremities if needed.³

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration.

Orally

One tablet, 0.2 mg, 3 or 4 times daily in the puerperium for a maximum of 1 week.

Tablets

0.2 mg round, coated, orchid, branded “78-54” one side, “SANDOZ” other side.

Bottles of 6............ NDC 12634-179-96

Bottles of 8............ NDC 12634-179-98

Bottles of 10 ..........NDC 12634-179-00

Bottles of 12 ..........NDC 12634-179-82

Bottles of 15.......... NDC 12634-179-85

Bottles of 20...........NDC 12634-179-80

Blister Pack of 1.... NDC 12634-179-91   

1. Information on Adverse Reactions supplied by Medical Services Department, Novartis Pharmaceuticals, E. Hanover, N.J., based on computerized clinical reports.
   
2. Berde, B. and Schild, H.O.: Ergot Alkaloids and Related Compounds, Springer-Verlag, New York, 1978, p. 810.
   
3. Treatment of Acute Overdosage. Novartis Consumer Health, Inc. Rx Products. Novartis, Medical Services Department.

T2006-91

REV: OCTOBER 2006             Printed in the U.S.A.                         5000981

5000982

Distributed by:

Novartis Pharmaceuticals Corporation

East Hanover, New Jersey 07936

© Novartis

Methergine® Trademark Registrant Sandoz Chemical Works, Inc.

By change of name, by merger, by assignment, List Owner Novartis Pharmaceutcals Corporation.