Donitriptan monohydrochloride is primarily used in the treatment of migraine headaches. It works by narrowing the blood vessels around the brain, which helps to alleviate the pain associated with migraines. Additionally, it reduces substances in the body that can trigger headache pain, nausea, sensitivity to light, and other migraine symptoms. This medication is particularly effective when taken at the onset of migraine symptoms to prevent the headache from becoming severe. It is also used to manage cluster headaches, providing relief from the intense pain and accompanying symptoms. Donitriptan monohydrochloride is typically administered in tablet form, ensuring ease of use for patients experiencing acute migraine attacks.