Methylergometrine maleate is a semi-synthetic ergot alkaloid derivative and a potent uterotonic agent. It is a direct-acting agonist on uterine smooth muscle, primarily used in the management of postpartum hemorrhage (PPH) and to aid in uterine involution following delivery. In the Indian context, it is a critical component of active management of the third stage of labor (AMTSL) and is widely available in hospital and clinical settings. It is more potent and has a more rapid onset of action than its parent compound, ergometrine.
Adult: **Postpartum:** 0.2 mg orally three to four times daily for a maximum of 7 days. For acute PPH: 0.2 mg IM or by slow IV injection (over at least 60 seconds); may be repeated as needed, not exceeding 1 mg total dose.
Note: **Oral:** Can be taken with or without food. **Parenteral:** For IM use, inject deep into a large muscle mass. For IV use, administer SLOWLY over no less than 60 seconds with constant monitoring of BP and uterine response. Rapid IV injection can cause severe hypertension, CVA, seizures. NEVER give intra-arterially. Should be administered only in a setting where facilities for managing hypertensive crises are available.
Methylergometrine acts as a partial agonist/antagonist at serotonin (5-HT2) receptors and as an agonist at alpha-adrenergic receptors. Its primary uterotonic effect is mediated through direct stimulation of serotonin receptors (5-HT2A) on the uterine smooth muscle, leading to a sustained increase in tone, frequency, and amplitude of contractions. This differs from oxytocin, which acts via oxytocin receptors.
Pregnancy: **Category X.** Contraindicated for use during pregnancy as it may induce abortion or fetal distress. Its use is strictly reserved for the postpartum period after delivery of the baby and as part of active management of the third stage of labor.
Driving: May cause dizziness, blurred vision, or weakness. Patients should be cautioned not to drive or operate machinery until they know how the drug affects them.
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin, Ritonavir) | Markedly increased methylergometrine plasma levels, leading to severe vasospasm, ischemia, gangrene. | Contraindicated |
| Vasoconstrictors (e.g., Sympathomimetics like Epinephrine, Norepinephrine) | Potentiated hypertensive effect, risk of severe hypertension and stroke. | Major |
| Propranolol and other non-selective beta-blockers | May enhance vasoconstrictive effects, increasing risk of peripheral ischemia. | Moderate |
| Nitrates (e.g., Nitroglycerin) | Nitrates may counteract the coronary vasospasm induced by methylergometrine. | Moderate (Therapeutic) |
| Macrolide antibiotics (except Azithromycin), Antifungals (azole class) | Increased ergot toxicity due to CYP3A4 inhibition. | Major/Contraindicated |
| Triptans (e.g., Sumatriptan), Other Ergot Alkaloids | Additive vasoconstrictive effect; increased risk of cerebral and coronary vasospasm. A 24-hour separation is mandated. | Contraindicated |
Same composition (Methylergometrine (0.2mg)), different brands: