Pharmacology · Ergot alkaloids
Ergometrine !
Ergot alkaloid on the WHO essential list that contracts the uterus to control bleeding after birth. Like methylergometrine, it is avoided in hypertension.
Updated 2026-11-01
Also called: Ergonovine
The figure shows methylergometrine, the methylated derivative of ergometrine, bound to the serotonin 5-HT2B receptor; ergometrine occupies the same kind of site.
Mechanism of action
Ergometrine is the parent compound of methylergometrine. It stimulates serotonin and alpha-adrenergic receptors of the uterus and produces a strong, sustained contraction that compresses the vessels of the placental bed. The same effect on blood vessels raises blood pressure.
- It stimulates 5-HT2 and alpha-adrenergic receptors of the uterus
- The uterus contracts strongly and stays contracted
- Bleeding from the placental bed falls; vessels also constrict
Pharmacokinetics
- Absorption
- Given IM or slowly IV
- Metabolism
- Liver, through CYP3A4, like the other ergot alkaloids
Indications
- Postpartum haemorrhage due to uterine atony, when hypertension has been excluded Postpartum haemorrhage →
Adverse effects
Common
- Nausea and vomiting
- Headache
- High blood pressure
- Abdominal pain
Contraindications
- Hypertension, pre-eclampsia and eclampsia
- Heart disease, especially coronary artery disease
- Pregnancy before birth
- Use with strong CYP3A4 inhibitors
Key interactions
- Macrolides, HIV protease inhibitors, azole antifungals
- CYP3A4 inhibition: higher levels and risk of severe vasospasm
- Other vasoconstrictors
- Additive vasoconstriction and hypertension
- Oxytocin and prostaglandins
- Additive uterotonic effect
What is monitored
- Blood pressure before and after the dose
- Uterine tone and blood loss
- Chest pain and signs of limb ischaemia
Administration and safety
- Check blood pressure first; it is not used in hypertension or pre-eclampsia.
- IV injection is slow, with blood pressure checks.
- Store as the label states (injectable ergot alkaloids are usually kept cold and protected from light) and away from newborn medicines.
Nursing care
- Before the dose: blood pressure and history of hypertension, pre-eclampsia or heart disease.
- After the dose: blood pressure, uterine tone, lochia and pain.
- Report chest pain, severe headache or cold, pale fingers.
- Check the medicine list for CYP3A4 inhibitors.
Pregnancy and breastfeeding
Contraindicated before birth because it contracts the uterus; it is used after the birth to control bleeding.
Test yourself
Think of the answer, then tap the question to see it.
What is the relation between ergometrine and methylergometrine?
Methylergometrine is the methylated derivative of ergometrine; both are ergot alkaloids that contract the uterus and raise blood pressure.
Which condition must be excluded before using ergometrine for bleeding after birth?
High blood pressure, including pre-eclampsia.
Which enzyme metabolises ergot alkaloids and is behind their dangerous interactions?
CYP3A4; its strong inhibitors raise ergot levels and can cause ergotism.
Related drugs
Related conditions
← Back to the class: Ergot alkaloids
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: eEML - Electronic Essential Medicines List (World Health Organization, 2025); WHO recommendations: uterotonics for the prevention of postpartum haemorrhage (World Health Organization, 2018); DailyMed - METHYLERGONOVINE MALEATE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.