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Pharmacology · Ergot alkaloids

Ergotamine !

Ergot alkaloid that narrows cranial blood vessels to stop migraine attacks. Dangerous with CYP3A4 inhibitors and forbidden in pregnancy.

Updated 2026-11-01

  • Class: Ergot alkaloids
  • Receptor: Serotonin 5-HT1B/1D receptors (and alpha-adrenergic receptors)
  • ATC code: N02CA02

Crystal structure of the human serotonin 5-HT1B receptor with ergotamine bound.

Target in 3D: Serotonin 5-HT1B/1D receptors (and alpha-adrenergic receptors). PDB structure 4IAR (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Ergotamine acts on serotonin receptors (especially 5-HT1B/1D) and alpha-adrenergic receptors. It constricts dilated cranial and peripheral blood vessels and depresses central vasomotor centres, which stops a migraine attack. Caffeine is often combined with it to add vasoconstriction. It also contracts the uterus.

  1. It binds 5-HT1B/1D and alpha-adrenergic receptors
  2. Dilated cranial vessels constrict
  3. The migraine attack is aborted; peripheral vessels also narrow

Pharmacokinetics

Absorption
By mouth, often with caffeine; also rectal when nausea is severe
Metabolism
Liver, through CYP3A4; it also inhibits CYP3A itself

Indications

Adverse effects

Common

  • Nausea and vomiting
  • Numbness, tingling and weakness of limbs
  • Cold hands and feet
  • Fast or slow heart rate and raised blood pressure

Contraindications

  • Pregnancy, labour and delivery
  • Peripheral vascular disease, coronary heart disease and hypertension
  • Liver or kidney impairment, and sepsis
  • Use with strong CYP3A4 inhibitors (protease inhibitors, macrolides, ketoconazole, itraconazole)

Key interactions

Strong CYP3A4 inhibitors (protease inhibitors, clarithromycin, erythromycin, ketoconazole, itraconazole)
Life-threatening peripheral ischaemia; contraindicated
Weaker CYP3A4 inhibitors (fluconazole, fluoxetine, grapefruit juice)
Higher levels; caution
Other vasoconstrictors or sympathomimetics
Additive vasoconstriction
Propranolol
May potentiate vasoconstriction

What is monitored

  • Pulses, colour and temperature of the limbs
  • Blood pressure and chest pain
  • Frequency of use (risk of rebound headache and fibrosis)

Administration and safety

  • Used at the start of an attack; chronic daily use is avoided.
  • Check the full medicine list for CYP3A4 inhibitors before each new prescription.
  • Contains tartrazine in some tablets: possible allergic reactions in people sensitive to aspirin.

Nursing care

  • Ask about pregnancy, heart disease, hypertension and peripheral vascular disease before use.
  • Teach the patient to report numbness, tingling, cold or pale fingers and chest pain at once.
  • Review new antibiotics, antifungals or HIV medicines for interactions.
  • Teach that overuse causes rebound headache.

Pregnancy and breastfeeding

Contraindicated: its oxytocic and vasoconstrictor effects can harm the fetus.

Test yourself

Think of the answer, then tap the question to see it.

Which serious reaction occurs when ergotamine is combined with a strong CYP3A4 inhibitor?

Life-threatening peripheral ischaemia (ergotism) from intense vasoconstriction.

Why is ergotamine contraindicated in pregnancy?

It contracts the uterus and constricts vessels, which can harm the fetus.

Which complication appears with long-term ergotamine use?

Fibrosis: retroperitoneal, pleuropulmonary or of the heart valves.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - ERGOTAMINE TARTRATE AND CAFFEINE tablet, film coated (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.