Sumatriptan succinate (Imitrex^®) is a prescription drug used for the treatment of migraine headaches. Part of a class of migraine medications called 5-HT agonists (or more commonly known as "triptans"), sumatriptan works by causing the blood vessels in the head to return to their normal state after dilating during a migraine. In one previous study, as many as 79 percent of people who had taken sumatriptan tablets had migraine relief within four hours, compared to just 38 percent of people who had not taken sumatriptan. Among the conditions you should let your healthcare provider know about before taking sumatriptan are diabetes, kidney or liver problems, and epilepsy. A few side effects of sumatriptan include dizziness, flushing, and warm or cold sensations. You must take sumatriptan as prescribed in order for it to work properly.