List of products in the National Drug Code with proprietary name . Dihydroergotamine is used to treat migraine headaches and cluster headaches. It is not recommended for migraines that affect only one side of the brain (hemiplegic migraine) or the base of the brain/neck area (basilar migraine), or to prevent migraines from occurring. Dihydroergotamine is an ergot medication that helps narrow widened blood vessels in the head, thereby reducing the throbbing effects of these headaches.