Methylergonovine (Methergine)

Emergency & Prehospital

• Postpartum uterine atony, hemorrhage and subinvolution: standard care once the placenta is out (label indication)
• Second-stage hemorrhage: bleeding control after the anterior shoulder is delivered. Labeled in the American Regent injection label, not in the Breckenridge label.

ED / ICU / Transport

• Postpartum hemorrhage that continues after first-line uterotonic: a second-line uterotonic, per local protocol and medical direction. The label does not give a second-line sequence.

Other Uses

• Before placenta delivery: not a label use. Give it only with obstetric direction and protocol. Uterine tetany can trap the placenta. An undiagnosed second twin is a risk.
• Not labeled for antepartum use: contraindicated in pregnancy. The uterotonic effect includes inducing labor.
• Not a prophylactic indication: the label covers postpartum treatment, not routine prophylaxis. Prevention falls to oxytocin, per protocol.

Doses vary by protocol; follow local protocols and medical direction.

Available Forms

• Injection 0.2 mg/mL: 1 mL ampule (0.2 mg); store in refrigerator (2–8 °C)
• Oral tablet 0.2 mg: Methergine and generic tablets; store below 25 °C in a tight, light-resistant container

Adult Dosing

Pediatric Dosing

Preparation & Administration

• IM: 1 mL (0.2 mg) into the muscle once the placenta is out. The label also allows it after the anterior shoulder or during the puerperium. Not before placenta delivery unless obstetric direction says so (see Indications).
• IV: 1 mL (0.2 mg) pushed slowly, over no less than 60 seconds. The label says nothing about dilution, admixture or push rate beyond that. Strictly avoid intra-arterial or periarterial injection (label).
• Ampule check: administer only if the solution is clear and colorless (label).
• Light and storage: ampules refrigerated at 2–8 °C (36–46 °F), protected from light. Tablets stored below 25 °C (77 °F) in a light-resistant container.
• Infusion: None. The label describes no continuous infusion, so no pump is needed.

Contraindications

• Hypertension
• Toxemia (preeclampsia)
• Pregnancy: contraindicated because of its uterotonic effects
• Hypersensitivity to methylergonovine
• Strong and moderate CYP3A4 inhibitors: the label says they should not be co-administered (see Interactions)

Precautions

• Sepsis and obliterative vascular disease: the label says use caution.
• Coronary artery disease or its risk factors: they are more likely to get myocardial ischemia or infarction from vasospasm.
• Weak CYP3A4 inhibitors: use with caution (label).
• Beta-blockers: may strengthen the vasoconstriction that ergot alkaloids cause.
• IV use: the label says not to give it IV routinely. Sudden hypertensive and cerebrovascular events are possible.
• Intra-arterial or periarterial injection: Strictly avoid it (label).
• Hepatic or renal impairment: no studies exist in either population. Use with caution (label).

Hold / Reassess If

• Blood pressure elevated: the label gives no numeric threshold; hypertension is the most common reaction. Stop and treat per protocol.
• Chest pain, ischemic ECG change or new arrhythmia: Stop and reassess per protocol. The label warns of vasospasm and myocardial ischemia.
• Limb pallor, coldness or pain: Possible vasospasm. Stop and reassess per protocol.

Common

• Hypertension: the most common adverse reaction on the label. In several cases it was linked to seizure and/or headache.

Serious / Life-Threatening

Overdose & Toxicity Management

• Signs (label): nausea, vomiting, oliguria, abdominal pain, numbness or tingling of the extremities, rise in blood pressure (in severe cases followed by hypotension), respiratory depression, hypothermia, convulsions and coma.
• Immediate management: stop methylergonovine. Monitor BP and ECG. The label describes supportive, symptom-based care: remove the drug (emesis or lavage), keep ventilation going, pressors for hypotension, standard anticonvulsants for convulsions and warmth for peripheral vasospasm.
• Antidote: The label states none. Antihypertensives per protocol (for example labetalol or hydralazine).
• Ongoing PPH: Escalate per protocol. This drug is no substitute for uterine massage, tranexamic acid or oxytocin.

Clinically Significant Interactions

IV Compatibility

• Diluent and admixture: the label offers no diluent, Y-site or admixture data.
• Push technique: Push 0.2 mg IV slowly, over at least 60 seconds. Watch BP during and after the dose.
• Dedicated line: the label sets no line requirement. Use a line you can monitor.
• Verify with an institutional compatibility resource.

• Pediatrics: Not established (label). See the Pediatric Dosing table. Do not extrapolate adult doses.
• Neonates: Infants can get the drug through breast milk during maternal treatment. The label says mothers should not breastfeed during treatment or for at least 12 hours after the last dose. Tell the neonatal team.
• Pregnancy: contraindicated because of its uterotonic effects. Label use comes after the placenta is delivered (or after the anterior shoulder, or in the puerperium). Before placenta delivery, use it only under obstetric direction. Tetanic contraction can trap the placenta. An undiagnosed second twin is a risk.
• Lactation: Mothers should not breastfeed during treatment. Discard the milk made in the 12 hours after the last dose (label).
• Older Adults: The labels reviewed establish no specific adjustment.
• Renal Impairment: Renal excretion helps clear the drug and its metabolites (label). No studies exist in renal impairment. Use with caution (label).
• Hepatic Impairment: The drug is mostly cleared by hepatic metabolism and excretion (label). No studies exist in hepatic impairment. Use with caution (label).
• Obesity / Dosing Weight: fixed dose; not weight-based.

• Scope: EMS use varies by state and agency protocol. A 2025 systematic review of prehospital uterotonics found limited evidence. Some systems carry oxytocin as their only uterotonic. Others carry none. Use is per protocol and medical direction.
• Storage & Stability: Injection stays refrigerated at 2–8 °C, away from light. Tablets stay below 25 °C. Don't leave ampules in a warm vehicle. Confirm the product in hand before use.
• Carried Concentration: 0.2 mg/mL ampule (1 mL = 0.2 mg) for IM or slow IV use. Read the label out loud. Methylergonovine and terbutaline (uterine relaxant) get confused with each other (see the terbutaline page).
• Infusions in Transport: none; no pump required.
• Altitude / Environment: not addressed in the label.
• Handoff Essentials: time, route and number of doses given; time of placenta or anterior shoulder delivery; BP before and after each dose; uterine tone; quantified blood loss; time of oxytocin and tranexamic acid, if given.

Mechanism of Action

• Target: uterine smooth muscle. The label says it acts directly on the uterus and names no receptor
• Effect: it raises the tone, rate and amplitude of rhythmic contractions. The result is a rapid, sustained, tetanic uterotonic effect (label)
• Consequence: a sustained squeeze on the uterus that limits bleeding from the placental site after delivery
• Off-target: ergot-type vasoconstriction. The label warns of vasospasm, hypertension and myocardial ischemia

Pharmacokinetics

• Half-life: mean elimination half-life 3.39 hr (range 1.5–12.7 hr) after IM dosing (label)
• Metabolism: Mostly hepatic metabolism and excretion. Clinical Pharmacology names no metabolizing enzyme. CYP3A4 interactions are listed under Interactions.
• Active metabolites: the label mentions the drug's metabolites but names none
• Elimination: renal excretion helps clear it (label)

Generic Name

Methylergonovine maleate

Brand Names

Methergine (US; injection and tablets); multiple generic injections and tablets from several labelers

Pharmacologic Class

Ergot alkaloid

Therapeutic Class

Uterotonic (postpartum)

Controlled Substance

Not controlled (DailyMed DEA schedule: none)

ISMP High-Alert

Not set as high-alert on this page; not checked against the current ISMP acute-care list in this review

Look-Alike / Sound-Alike

Methergine / Brethine (terbutaline), as cited on the terbutaline page

Error-Prone Abbreviations to Avoid

None commonly reported