About Rizatriptan Serotonin 5-HT1B, 1D Receptor Agonist, Antimigraine. Mechanism of Action of Rizatriptan Rizatriptan is a 5-hydroxytriptamine1B/1D receptor agonist. Rizatriptan relieves migraines by constricting cranial blood vessels of the carotid circulation and reduces blood flow. It also inhibits the release of neuropeptides responsible for pain. Indications for Rizatriptan Migraine Interactions for Rizatriptan Antibacterials: quinolones possibly reduce metabolism of Rizaitriptan. Avoid concomitant use with clarithromycin and erythromycin. Antidepressants: risk of CNS toxicity with MAOIs. Beta blockers: Propranolol may increase plasma concentration of Rizatriptan. Ergotamine: Increased risk of vasospasm.