Ergotamine: Ergot Alkaloid in Acute Migraine Therapy

Ergotamine is a classic ergot alkaloid derived from the fungus Claviceps purpurea, which settles on rye and other grain crops. It has been used pharmaceutically since the 1920s, and in acute migraine therapy, ergotamine was for a long time the only specific treatment option. Well-known brand names include Ergo Kranit, Migrätan, and ergotamine tartrate in combination preparations with caffeine (Cafergot).

Today, ergotamine plays only a minor role in modern migraine therapy. With the introduction of triptans in the 1990s, it was largely displaced because triptans are more effective and better tolerated. A current indication for ergotamine exists only in patients with prolonged migraine attacks (over 24 hours) in whom triptans frequently lead to recurrent headache, or in cluster headache attacks. In Germany, ergotamine preparations are barely available anymore; the active substance dihydroergotamine (DHE) is the preferred variant.

Mechanism of Action

Ergotamine is a partial agonist and antagonist at several biogenic amine receptors. It acts agonistically at serotonin (5 HT1B/1D), dopamine, and alpha adrenergic receptors. The antimigraine effect is primarily based on activation of 5 HT1B/1D receptors in meningeal vessels, similar to modern triptans. This results in vasoconstriction of dilated cranial vessels and inhibition of the release of neurogenic inflammatory peptides such as CGRP at trigeminal nerve endings.

The vasoconstriction, however, is non-selective and affects peripheral and coronary vessels as well, which explains the cardiovascular risks. The agonistic effect at alpha adrenergic receptors further enhances vasoconstriction. At 5 HT2 receptors, ergotamine acts partially antagonistically, which contributes to reduction of peripheral pain fiber stimulation.

Pharmacokinetically, ergotamine has poor and variable oral bioavailability of approximately 5 percent due to high first-pass metabolism. Caffeine in combination preparations improves absorption. Half-life approximately two hours, with active metabolites considerably prolonging the effect.

Indications

• Acute migraine therapy: in prolonged attacks lasting over 24 hours when triptans are insufficient due to recurrent headache
• Acute cluster headache therapy: historically and off-label, especially for nocturnal attacks
• Status migraenosus: historically, now superseded by intravenous dihydroergotamine (DHE)
• Postpartum uterine atony: historically used, now superseded by oxytocin and misoprostol

Dosage and Administration

Acute migraine in adults: 1 to 2 mg orally or rectally at the first sign of an attack; if necessary, an additional 1 mg after 30 minutes, maximum 4 mg per attack. Weekly maximum 10 mg, monthly maximum 20 mg to avoid ergotism and medication-overuse headache.

Frequency of use: no more than ten days per month, otherwise risk of medication-overuse headache (MOH). Ergotamine therapy should only be undertaken in consultation with a healthcare provider experienced in migraine management.

Renal and hepatic impairment: contraindicated due to risk of accumulation and ergotism.

Adverse Effects

Frequent: nausea, vomiting (sometimes worsened by the migraine itself), abdominal pain, dizziness, fatigue, paresthesias in fingers and toes.

Serious: ergotism from chronic or high-dose use with pronounced peripheral vasoconstriction (cold, pale extremities, absent pulses, ischemia, in severe cases gangrene), cardiac ischemia to myocardial infarction, cerebral ischemia to stroke, retroperitoneal, pleural, and cardiac fibrosis with long-term use.

Important: patients with cardiovascular disease, peripheral arterial occlusive disease, hypertension, pregnancy, or chronic renal insufficiency must not receive ergotamine. Use in children and adolescents is contraindicated.

Drug Interactions

• Triptans (sumatriptan, zolmitriptan): additive vasoconstriction, combination contraindicated; at least 24 hours washout required
• Strong CYP3A4 inhibitors (ketoconazole, itraconazole, erythromycin, clarithromycin, HIV protease inhibitors): substantial increase in ergotamine levels with risk of severe ergotism, combination contraindicated
• Other vasoconstrictive agents (sympathomimetics, beta blockers): additive effects, caution advised
• Ergot alkaloids among themselves: additive effect, avoid combination
• Nicotine: substantially enhances vasoconstriction, smoking cessation recommended during therapy

Special Notes

Pregnancy and breastfeeding: contraindicated. Ergotamine has uterotonic effects and can induce labor or reduce placental blood flow. In breastfeeding, it passes into breast milk and can cause vomiting, diarrhea, and seizures in infants.

Triptans as modern alternative: sumatriptan, zolmitriptan, rizatriptan, and other triptans have largely replaced ergotamine in migraine therapy. They act more selectively at 5 HT1B/1D receptors, cause less systemic vasoconstriction, and are better tolerated even by older patients. CGRP antibodies additionally offer a prophylaxis option.

Medication-overuse headache: regular use of ergotamine on more than ten days per month typically leads to a paradoxical worsening of headaches. In this case, withdrawal is necessary, often with inpatient support.

Ergotism: historical cases of St. Anthony's Fire (ergot poisoning) from contaminated rye flour in the Middle Ages demonstrate the consequences of overdose. Today, classical ergotism is rare, but any symptom of coldness, pallor, or pain in the extremities during ergotamine therapy should prompt immediate discontinuation and medical evaluation.

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• Propranolol, beta blocker for migraine prophylaxis

Frequently Asked Questions

Sources

• Gelbe Liste, Ergotamine Active Ingredient Profile
• DGN Guideline Therapy of Migraine Attack and Prophylaxis
• BfArM, Federal Institute for Drugs and Medical Devices
• EMA Product Information Ergotamine Preparations