1 ML methylergonovine maleate 0.2 MG/ML Injection

INDICATIONS AND USAGE Following delivery of the placenta, for routine management of uterine atony, hemorrhage and subinvolution of the uterus. For control of uterine hemorrhage in the second stage of labor following delivery of the anterior shoulder.

DOSAGE AND ADMINISTRATION Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration. Intramuscularly 1 mL, 0.2 mg, after delivery of the anterior shoulder, after delivery of the placenta, or during the puerperium. May be repeated as required, at intervals of 2 to 4 hours. Intravenously 1 mL, 0.2 mg, administered slowly over a period of no less than 60 seconds (See WARNINGS .) Orally The recommended dosage of methylergonovine maleate is One tablet, 0.2 mg, orally 3 or 4 times daily in the puerperium for a maximum of 1 week.

WARNINGS General 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, 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 presence of impaired hepatic or renal function. Breast-feeding Mothers should not breast-feed during treatment with methylergonovine maleate tablets, USP. Milk secreted during this period should be discarded. Methylergonovine maleate tablets, USP may produce adverse effects in the breast-feeding infant. Methylergonovine maleate tablets, USP may also reduce the yield of breast milk. Mothers should wait at least 12 hours after administration of the last dose of methylergonovine maleate tablets, USP before initiating or resuming breast feeding. Coronary artery disease Patients with coronary artery disease or risk factors for coronary artery disease (e.g., smoking, obesity, diabetes, high cholesterol) may be more susceptible to developing myocardial ischemia and infarction associated with methylergonovine-induced vasospasm. Medication errors Inadvertent administration of methylergonovine maleate tablets, USP to newborn infants has been reported. In these cases of inadvertent neonatal exposure, symptoms such as respiratory depression, convulsions, cyanosis and oliguria have been reported. Usual treatment is symptomatic. However, in severe cases, respiratory and cardiovascular support is required. Methylergonovine maleate tablets, USP have been administered instead of vitamin K and Hepatitis B vaccine, medications which are routinely administered to the newborn. Due to the potential for accidental neonatal exposure, methylergonovine maleate should be stored separately from medications intended for neonatal administration.

CONTRAINDICATIONS Hypertension; toxemia; pregnancy; and hypersensitivity.

CLINICAL PHARMACOLOGY Mechanism of Action 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. Pharmacodynamics The onset of action after IV administration is immediate; after IM administration, 2 to 5 minutes, and after oral administration, 5 to 10 minutes. Pharmacokinetics Pharmacokinetic studies following an IV injection have shown that methylergonovine is rapidly distributed from plasma to peripheral tissues within 2 to 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. A delayed gastrointestinal absorption (T max about 3 hours) of methylergonovine tablet might be observed in postpartum women during continuous treatment with this oxytoxic agent. For a 0.2 mg intramuscular (IM) 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 IM intramuscular solution given orally, and the extent of oral absorption of the IM intramuscular 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 methylergonovine maleate solution was about 25% greater than the tablet. The volume of distribution (Vd ss /F) of intramuscularly administered 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 decline of plasma level of intramuscularly administered methylergonovine was biphasic with a mean elimination half-life of 3.39 hours (range 1.5 to 12.7 hours).