What are the contraindications of ergometrine?

Contraindications of Ergometrine

Ergometrine is contraindicated in patients with hypertension, pre-eclampsia/eclampsia, cardiovascular disease, respiratory disease (particularly asthma), sepsis, and hypersensitivity to the drug. 1, 2

Major Contraindications

Cardiovascular Contraindications

• Hypertension (any severity) 1
• Pre-eclampsia and eclampsia 1, 3
• Coronary artery disease 2
• Cerebrovascular disease 2
• Obliterative vascular disease 1

Respiratory Contraindications

• Asthma and other respiratory diseases 2, 4
• Risk of bronchospasm, particularly when used with general anesthetics 2

Other Absolute Contraindications

• Pregnancy (due to uterotonic effects) 1
• Hypersensitivity to ergometrine 1
• Sepsis 1

Mechanism of Adverse Effects

Ergometrine can cause serious adverse effects through several mechanisms:

1. Vasoconstriction: Ergometrine causes potent vasoconstriction that can lead to:

   • Coronary vasospasm and ischemia 2
   • Cerebral vasospasm 1
   • Peripheral vasospasm 1

2. Bronchospasm: Can trigger bronchospasm in susceptible individuals, particularly those with asthma 2

3. Hypertensive crisis: Can dramatically increase blood pressure in hypertensive patients 3

4. Precipitation of eclamptic seizures: In patients with undiagnosed or existing pre-eclampsia 3

Drug Interactions

Ergometrine should be avoided with:

• CYP3A4 inhibitors (especially potent ones like macrolide antibiotics, HIV protease inhibitors, azole antifungals) 1
• Beta-blockers: May enhance vasoconstrictive effects 1
• Other vasoconstrictors: Additive effects increasing risk of severe vasoconstriction 1
• Anesthetics: Halothane and methoxyflurane may alter ergometrine's effects 1
• Glyceryl trinitrate and antianginal drugs: Ergometrine may reduce their effectiveness 1

Special Populations

Breastfeeding

• Mothers should not breastfeed during treatment with ergometrine and for at least 12 hours after administration 1
• Any milk secreted during this period should be discarded 1

Elderly

• Lower doses should be used in elderly patients due to:
  • Decreased hepatic function
  • Decreased renal function
  • Increased likelihood of cardiovascular disease 1

Clinical Considerations

Safer Alternatives

• Oxytocin is preferred over ergometrine for prevention of postpartum hemorrhage, particularly in women with respiratory or cardiovascular disease 2, 4, 5
• For women with lung disease, active management of the third stage of labor should use oxytocin without ergometrine 2

Efficacy vs. Safety

• While ergometrine is effective for preventing postpartum hemorrhage, its severe and unpredictable side effects make it less favorable than alternatives like oxytocin 6, 5
• Studies show that oxytocin is more effective than ergometrine for prevention of postpartum hemorrhage (288.16g vs 354.42g mean blood loss) with fewer side effects 5

Monitoring

When ergometrine must be used (in absence of contraindications):

• Monitor blood pressure closely
• Watch for signs of vasospasm (chest pain, extremity pain)
• Be alert for respiratory distress
• Observe for signs of eclampsia if there's any possibility of undiagnosed pre-eclampsia 3

Summary

Ergometrine should be avoided in patients with cardiovascular conditions, respiratory diseases, pregnancy, and hypersensitivity reactions. The risk of serious adverse events including vasospasm, hypertensive crisis, and bronchospasm makes oxytocin a safer alternative in most clinical scenarios where uterotonic effects are needed.