Imigran nasal spray contains a single dose of sumatriptan which belongs to a group of medicines called triptans imigan spray is used to treat migraines migraine symptoms by temporary widening of blood vessels in the head imigran nasal spray is believed to reduce the widening of these blood vessels which in turn helps to take away the headache this will also help reduce the symptoms of a migraine attack such as feeling or being sick nausea or vomiting and sensitivity to light and sound