Clinical safety rating: caution
Uterotonic ergot alkaloid used for prevention and treatment of PPH after delivery of the placenta. Effective but has significant contraindications: causes vasoconstriction and is contraindicated in hypertension, preeclampsia, and cardiovascular disease — which are common comorbidities in obstetric PPH scenarios. Oxytocin and misoprostol are preferred first-line agents; ergometrine is reserved for refractory cases or used in combination (Syntometrine = oxytocin + ergometrine). Must not be used before delivery of the baby — severe uterine tetany and fetal hypoxia.
Ergometrine and methylergonovine are ergot alkaloids that act as partial agonists at alpha-adrenergic, dopaminergic, and serotonergic (5-HT2) receptors. Their primary uterotonic effect is mediated by stimulation of 5-HT2 receptors in uterine smooth muscle, leading to sustained contractions and vasoconstriction.
| Metabolism | Primarily hepatic via CYP3A4; also undergoes first-pass metabolism. Metabolites are excreted in urine and bile. |
| Excretion | Renal (20% unchanged), biliary/fecal (35% as metabolites and parent compound) |
| Half-life | 30-120 min (biphasic: initial 10 min, terminal 30-120 min); clinical context: short half-life allows repeated dosing for postpartum hemorrhage but requires monitoring for accumulation |
| Protein binding | 85-90% (primarily to albumin and α1-acid glycoprotein) |
| Volume of Distribution | 0.4-0.6 L/kg; clinical meaning: moderate tissue distribution, consistent with limited extravascular binding |
| Bioavailability | Oral: 20-40% (due to extensive first-pass metabolism); IM: ~80% |
| Onset of Action | IV: 40-60 sec; IM: 2-5 min; Oral: 5-15 min |
| Duration of Action | IV: 45 min; IM: 3-6 hours; Oral: 3-6 hours; clinical notes: uterine effects last longer than vasopressor effects |
| Molecular Weight | 339.4 |
0.2 mg intramuscularly or intravenously, repeated every 2-4 hours as needed, up to 5 doses total. Maximum single dose: 0.5 mg. Maximum total dose: 1 mg.
| Renal impairment | No specific guidelines; use with caution in severe renal impairment (GFR <30 mL/min) due to risk of accumulation and hypertensive effects. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval. Child-Pugh Class C: avoid use. |
| Pediatric use | 0.1-0.2 mg intramuscularly or intravenously every 2-4 hours as needed; maximum single dose 0.2 mg. For postpartum hemorrhage, 0.2 mg IM/IV repeated every 2-4 hours, max 5 doses. |
| Geriatric use | Use lowest effective dose due to increased sensitivity and higher risk of hypertension and coronary vasospasm; consider 0.1 mg initially and titrate cautiously. |
| 1st trimester | No data; use only if benefit outweighs risk. Uterotonic effects may cause fetal hypoxia. |
| 2nd trimester | Avoid; risk of uterine hyperstimulation and fetal distress. |
| 3rd trimester | Avoid; used postpartum for hemorrhage, not during labor unless for third stage management. |
Clinical note
Uterotonic ergot alkaloid used for prevention and treatment of PPH after delivery of the placenta. Effective but has significant contraindications: causes vasoconstriction and is contraindicated in hypertension, preeclampsia, and cardiovascular disease — which are common comorbidities in obstetric PPH scenarios. Oxytocin and misoprostol are preferred first-line agents; ergometrine is reserved for refractory cases or used in combination (Syntometrine = oxytocin + ergometrine). Must not be used before delivery of the baby — severe uterine tetany and fetal hypoxia.
| Placental transfer | Crosses placenta; rapid transfer observed in animal studies. Human data limited. |
| Breastfeeding |
■ FDA Black Box Warning
Concurrent use with potent CYP3A4 inhibitors (e.g., macrolide antibiotics, protease inhibitors, azole antifungals) may result in acute ergot toxicity (vasospasm, cerebral and peripheral ischemia). Contraindicated in pregnancy for induction of labor due to risk of uterine rupture and fetal harm.
| Serious Effects |
Hypersensitivity to ergot alkaloidsPeripheral vascular diseaseHypertensionPreeclampsia/eclampsiaSepsisCoronary artery diseaseProlonged use in pregnancy (oxytocic effect)
| Precautions | May cause hypertension, especially in patients with preeclampsia or hypertension. Use with caution in patients with sepsis, hepatic or renal impairment, coronary artery disease, or peripheral vascular disease. Avoid prolonged use. Monitor uterine tone and bleeding. |
| Food/Dietary | No known food interactions. |
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| Excreted into breast milk in small amounts; may cause ergotism in infants with prolonged exposure. Avoid in breastfeeding unless essential for postpartum hemorrhage. |
| Lactation Rating | L4 |
| Teratogenic Risk | First trimester: Limited human data; animal studies show embryotoxicity and fetotoxicity at high doses due to uterotonic effects, but no structural malformations. Increased risk of spontaneous abortion from uterine hyperstimulation. Second trimester: Uterotonic effects may cause placental abruption, preterm labor, or fetal hypoxia. Third trimester: Contraindicated due to potent uterotonic activity; can cause uterine tetany, fetal distress, and stillbirth. Avoid during pregnancy unless for postpartum hemorrhage. |
| Fetal Monitoring | Maternal: Monitor blood pressure (risk of hypertension), uterine tone, and signs of ergotism (nausea, vomiting, peripheral ischemia). Fetal/neonatal: Heart rate monitoring during administration; assess for signs of hypoxia or distress if used before delivery. |
| Fertility Effects | No specific adverse effects on fertility documented. Ergot alkaloids inhibit prolactin secretion, which may theoretically reduce ovulation or luteal function, but this is not clinically relevant with acute use. |
| Clinical Pearls | Administer intramuscularly or intravenously (slow push over 1 minute) for uterine atony; avoid in hypertension, preeclampsia, and sepsis. Store ampules protected from light; discard if discolored. Contraindicated in impaired hepatic or renal function. |
| Patient Advice | This medication may cause nausea, vomiting, or headache. · Report severe abdominal pain, chest pain, or difficulty breathing immediately. · Avoid driving or operating machinery if dizziness occurs. · Do not use during pregnancy except for postpartum hemorrhage. · Inform your doctor if you have high blood pressure, heart disease, or are breastfeeding. |