An antimigraine drug. Zolmitriptan (Zomig) is used to treat severe migraine headaches. Zolmitriptan cannot prevent migraine but can only ease a migraine headache that is already occurring. Zolmitriptan relieves symptoms that are associated with migraine, including nausea, vomiting, and sensitivity to light and sound. It is thought to work by narrowing blood vessels in the brain that cause the pain.