Sumatriptan is a medication primarily used to treat acute migraine headaches with or without aura, as well as cluster headaches in adults. It belongs to the triptan class and acts as a selective serotonin (5-HT1B/1D) receptor agonist, working by narrowing blood vessels in the brain, blocking pain signal transmission to the brain, and inhibiting the release of substances that trigger nausea and sensitivity to light or sound. This helps relieve migraine intensity, often within three hours of administration via oral tablet, nasal spray, or subcutaneous injection, though it does not prevent future attacks or address underlying causes. Injected forms tend to act fastest and most effectively for severe episodes. It's also occasionally used for post-dural puncture headaches, with therapeutic effects stemming from vasoconstriction in cranial blood vessels and reduced trigeminovascular nerve activity.