Pharmacology IV – Headache Therapeutics Practice Test

Ergotamines work by acting as nonselective serotonin receptor agonists, producing vasoconstriction of cranial and other blood vessels. They stimulate multiple serotonin receptors, not just one subtype, with a prominent effect on receptors involved in vascular tone. This constriction reduces the pulsatile dilation and neurogenic inflammation thought to contribute to migraine symptoms, providing relief. Because they’re not highly selective, ergotamines also interact with other receptor systems (such as alpha-adrenergic and dopaminergic receptors), which helps explain their potent vasoconstrictive effects and broader side effects. This distinguishes them from drugs that are designed to be selective 5-HT1B/1D receptor agonists, like the triptans, which target a specific receptor subset to relieve migraine. In short, ergotamines are nonspecific serotonin receptor agonists with vasoconstrictive effects, rather than a dopamine antagonist, a CGRP receptor antagonist, or a strictly selective 5-HT1B/1D receptor agonist.