Sumatriptan is effective in aborting a migraine attack. Its MAIN mechanism of action is:
- A Selective agonism at 5-HT1B/1D receptors causing cranial vasoconstriction and inhibition of trigeminal nociceptive transmission ✓
- B Blockade of CGRP receptors on trigeminal nerve endings
- C Antagonism of substance P at NK1 receptors in the trigeminal ganglion
- D COX-2 inhibition reducing prostaglandin-mediated sensitisation of meningeal nociceptors
Correct answer: A. Selective agonism at 5-HT1B/1D receptors causing cranial vasoconstriction and inhibition of trigeminal nociceptive transmission
Explanation
Sumatriptan is a selective 5-HT1B/1D receptor agonist. 5-HT1B receptors on cranial blood vessels mediate vasoconstriction, reversing the meningeal vasodilation during migraine. 5-HT1D receptors on presynaptic trigeminal nerve terminals inhibit release of CGRP, substance P and other neuropeptides responsible for neurogenic inflammation and pain sensitisation. This dual vascular and neuronal action makes triptans highly effective migraine-specific abortives, but their vasoconstrictive effect contraindicates them in ischaemic heart disease.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.