About Sumatriptan Selective Serotonin 5-HT1B, 1D Agonist, Antimigraine Agent. Mechanism of Action of Sumatriptan Sumatriptan is a selective Serotonin (5HT1D) receptor agonist. It selectively constricts the large intracranial blood vessels of the carotid circulation and reduces the blood flow and relieves the migraine. Sumatriptan is used for the acute treatment of migraine attacks and of cluster headache. Indications for Sumatriptan 1. Acute attack of migraine treatment with or without aura Interactions for Sumatriptan Ergotamine containing preparations: Concomitant use should be avoided because of vasospastic reactions. MAOIs: Concomitant use within 2 weeks of discontinuation of MAOIs is contraindicated. Lithium: Concomitant use must be avoided.