Topic overview

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Ergot alkaloids have mixed agonist and antagonist activity at serotonin, α-adrenergic, and D₂ receptors. Their clinical roles differ by subgroup: ergotamine and dihydroergotamine are potent cerebral vasoconstrictors used for acute migraine; ergometrine (methylergometrine) produces sustained uterine contraction and is used for postpartum hemorrhage after oxytocin; and bromocriptine and cabergoline suppress prolactin through D₂ agonism. Their usefulness is limited by adverse effects and potentially severe toxicity. Ergotism can involve marked vasospasm, while longer-term use of some agents is associated with fibrotic reactions. Key safety topics include contraindications, CYP3A4 inhibitor interactions, coronary vasospasm risk, and avoiding use with triptans within 24 hours. The full lesson develops these points across classification, pharmacokinetics, clinical applications, and toxicity management.