Treximet is the brand name of a combination medication used to treat migraine headaches. Treximet contains two active ingredients: sumatriptan, which is a serotonin 5-HT1 receptor agonist (also called a triptan), and naproxen sodium, which is a nonsteroidal anti-inflammatory drug (an NSAID). Though Treximet can't prevent migraines, it can effectively treat and control the symptoms once a migraine attack starts. Triptans work by narrowing blood vessels in the brain, and NSAIDs work to relieve pain by blocking the development of certain chemicals (prostaglandins) in the body. Treximet is usually taken as soon as symptoms of a migraine are noticed.