Sumatriptan is primarily used in the treatment of migraine headaches and cluster headaches. It works by narrowing blood vessels in the brain, which helps to alleviate the pain and other symptoms associated with migraines, such as nausea, vomiting, and sensitivity to light and sound. It is often administered in the form of tablets, nasal sprays, or injections, depending on the severity and onset of the headache. Sumatriptan is effective in providing relief during the acute phase of a migraine attack, but it is not intended for use as a preventive medication. It is important to use this medication as soon as migraine symptoms appear for optimal results. However, overuse of sumatriptan can lead to medication-overuse headaches, so it should be taken strictly as prescribed by a healthcare professional.