 |
| |
|
|
|
|
DRUG DESCRIPTION
Metherlin (methylergonovine maleate) is a semi-synthetic ergot alkaloid used for the prevention and control of postpartum hemorrhage.
Active Ingredient: methylergonovine maleate, USP, 0.2 mg.
Inactive Ingredients: acacia, carnauba wax, D&C Red #7, FD&C Blue #1, gelatin special, lactose, maleic acid, mixed parabens, povidone, sodium benzoate, sodium hydroxide, starch, stearic acid, sucrose, talc, and titanium dioxide.
INDICATIONS
For routine management after delivery of the placenta; postpartum atony and hemorrhage; subinvolution. Under full obstetric supervision, it may be given in the second stage of labor following delivery of the anterior shoulder.
USES
This medication is used to help stop bleeding after delivery of the placenta in childbirth. Methylergonovine maleate belongs to a class of drugs known as ergot alkaloids. It works by increasing the stiffness of the uterus muscles after the last stage of labor. This effect decreases bleeding.
DOSAGE AND ADMINISTRATION
Intramuscularly
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 2-4 hours.
Intravenously
Dosage same as intramuscular.
Orally
One tablet, 0.2 mg, 3 or 4 times daily in the puerperium for a maximum of 1 week.
SIDE EFFECTS
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.
Drug Abuse And Dependence
Metherlin (methylergonovine maleate) has not been associated with drug abuse or dependence of either a physical or psychological nature.
WARNINGS
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, Metherlin (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.
PRECAUTIONS
Before taking methylergonovine maleate, tell your doctor or pharmacist if you are allergic to it; or to similar ergot alkaloids (e.g., ergonovine); or if you have any other allergies.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: high blood pressure, a certain complication of pregnancy (toxemia).
Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart disease (e.g., venoatrial shunt, mitral valve stenosis), other complications during pregnancy (e.g., pre-eclampsia, eclampsia), a serious blood infection (sepsis), blood vessel problems (e.g., Raynaud's phenomenon, obliterative vascular disease), kidney problems, liver problems.
This drug may make you dizzy or drowsy. Use caution while driving, using machinery, or doing any activity that requires alertness. Limit or avoid alcoholic beverages.
STORAGE
Store at room temperature below 77 degrees F (25 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children.
How should you take Methylergonovine maleate?
Take Methergine tablets exactly as prescribed.
* If you miss a dose...
Do not take the missed dose at all and do not double the next one. Instead, go back to your regular schedule.
* Storage instructions...
Store at room temperature in a tightly closed container, away from light.
What side effects may occur?
Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Methergine.
The most common side effect is high blood pressure, which may cause a headache or even a seizure. In some people, however, Methergine may cause low blood pressure.
Why should Methylergonovine maleate not be prescribed?
You should not take Methergine if you are allergic to it, if you are pregnant, or if you have high blood pressure or toxemia (poisons circulating in the blood).
Treatment of overdose
Immediate discontinuation of methylergonovine. Since there is no specific antidote for the management of methylergonovine overdose, treatment is primarily supportive and symptomatic and may include the following:
To decrease absorption:
Gastrointestinal decontamination for oral overdose, preferably with multiple doses of activated charcoal and an appropriate cathartic. Gastric lavage may also be considered.
Specific treatment:
Use of nitroglycerin for treatment of myocardial ischemia.
Intracoronary nitroglycerin may be necessary.
Use of diazepam or phenytoin for treatment of seizures.
Use of sodium nitroprusside, tolazoline, or phentolamine for treatment of peripheral ischemia.
Use of sodium nitroprusside, chlorpromazine 15 mg, or hydralazine for treatment of severe hypertension.
Monitoring:
Frequent monitoring of vital signs, arterial blood gases, and electrolytes. Electrocardiogram monitoring to assess cardiac function and perfusion. Monitoring of serum methylergonovine levels is not predictive of the outcome of overdose.
Supportive care:
May include maintaining an open airway and breathing, maintaining proper fluid and electrolyte balance, correcting hypertension, and controlling seizures. Patients in whom intentional overdose is known or suspected should be referred for psychiatric consultation.
Methergine® (methylergonovine maleate) is a semi-synthetic ergot alkaloid used for the prevention and control of postpartum hemorrhage.
Methergine is available in sterile ampuls of 1 mL, containing 0.2 mg methylergonovine maleate for intramuscular or intravenous injection and in tablets for oral ingestion containing 0.2 mg methylergonovine maleate.
Tablets
Active Ingredient: methylergonovine maleate, USP, 0.2 mg.
Inactive Ingredients: acacia, carnauba wax, D&C Red #7, FD&C Blue #1, gelatin special, lactose, maleic acid, mixed parabens, povidone, sodium benzoate, sodium hydroxide, starch, stearic acid, sucrose, talc, and titanium dioxide.
Ampuls, 1 mL, clear, colorless solution.
Active Ingredient: methylergonovine maleate, USP, 0.2 mg.
Inactive Ingredients: maleic acid, 0.10 mg; sodium chloride, 7.0 mg; water for injection, qs to 1 mL.
Methylergonovine maleate (methylergometrine maleate; methylergobasine maleate) is an ergot alkaloid derivative used in the treatment of postpartum and postabortion hemorrhage. It is contraindicated during pregnancy because it may cause sustained, tetanic uterine contractions and resulting fetal compromise.
Only one animal reproductive study has been located that has investigated the effect of methylergonovine on the fetus (1). Thirteen albino rats were administered 0.5 mg/kg intraperitoneally twice daily from the 12th day through the 21st day (second half of gestation) after sperm were found in the vaginal smears of the animals (1). Three other groups received different ergot alkaloids and another group acted as controls. Three (23%) of the methylergonovine group failed to conceive or resorbed their concepti compared with an average of 17% (10 of 58) in the other three treated groups and 17% (2 of 12) in the controls. The surviving pups were not examined for congenital malformations (drug-induced anomalies not expected), but their birth weights were similar to those of pups in the control group.
The Collaborative Perinatal Project monitored 50,282 mother-child pairs, 32 of which were exposed to ergot derivatives other than ergotamine during the 1st trimester (2). Five of this group were exposed to methylergonovine maleate; 18, to ergonovine; 5, to ergot; 3, to dihydroergotamine; and 1, to methysergide. Three children with any malformation were observed in the total group, but only one had a malformation considered easily recognizable among the 12 medical centers participating in the study. The authors concluded that, although the numbers were small, there was no evidence that these agents were teratogenic (2).
A 1979 report described the effects of methylergonovine on a woman in the first stage of labor (i.e., from onset of labor to full dilation of the cervix) at 43 weeks' gestation (3). The woman was accidentally given 0.2 mg methylergonovine IM that had been ordered for a postpartum patient. Within 20 minutes, uterine hypertonus was evident, and the fetal heart rate (FHR) decreased to 80 to 90 beats/minute with increased variability. IV epinephrine (0.5 mL of 1:1000) was administered, with a rapid decline in excessive uterine activity, but the FHR fell to 40 to 50 beats/minute (most likely because of epinephrine-induced vasoconstriction) before slowly returning to baseline. When uterine tetany returned, a second dose of epinephrine (1/6 mL) was required, producing similar effects on uterine activity and the FHR, but of shorter duration. A 6-pound 0.25-ounce (about 2731-g) male infant was delivered 6 hours later with Apgar scores of 5 and 7 at 1 and 5 minutes, respectively. Examinations of the infant over the next 9 months were normal.
A similar case of accidental (i.e., a dose intended for another patient) methylergonovine administration resulting in uterine hypertonus was reported in 1988 (4). The 18-year-old woman at 37 weeks' gestation in the first stage of labor with uterine contractions every 2 to 3 minutes and a partially dilated and effaced cervix received 0.2 mg methylergonovine IM. Six minutes later, the FHR fell from 150 to 70 beats/minute and uterine hypertonus was detected on palpation. Terbutaline, 0.25 mg IV, reversed the fetal bradycardia but did not relax the uterus. Magnesium sulfate, 4-g IV loading dose followed by 2 g/hour, also failed to reverse the hypertonus. Adverse changes in the fetus, including loss of FHR beat-to-beat variability, late decelerations, development of tachycardia (170 beats/minute), and acidosis (scalp pH 7.12), impelled the authors to perform a cesarean section, under general anesthesia, to deliver the 7-pound 15-ounce (about 3604-g) male infant. Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. At delivery, the umbilical artery blood had a pH of 7.13, confirming the diagnosis of metabolic acidosis (4). The infant did well after delivery and was discharged home at 4 days of age.
In summary, methylergonovine does not appear to be a major teratogen in either animals or humans, but the data are too limited for any conclusion. The drug is contraindicated during pregnancy because of its propensity to cause sustained, tetanic uterine contractions that result in fetal hypoxia. Because of this, it is used as an alternate drug to oxytocin for management of the third stage of labor (i.e., from delivery of the infant to delivery of the placenta) and for the treatment of postpartum or postabortion hemorrhage. Care must be taken before administering this agent to confirm that the intended recipient has delivered her fetus.
Contraindications
• Hypersensitivity to drug
• Hypertension
• Toxemia
• Pregnancy (except during third stage of labor)
Precautions
Use cautiously in:
• severe hepatic or renal disease, vascular disease, jaundice, sepsis
• patients in second stage of labor.
Administration
• Be aware that drug isn't routinely given I.V. because of risk of severe hypertension and cerebrovascular accident (CVA). Monitor blood pressure and uterine contractions during administration.
• If I.V. use is necessary, give dose over 1 minute. Dose may be diluted in 5 ml of 0.9% sodium chloride injection.
• Be aware that prolonged therapy should be avoided because of ergotism risk.
