Dihydroergotamine (DHE) is a prescription medication available in injectable and nasal forms that is used to relieve acute migraine attacks. It is among the most effective migraine treatments and considered safe for most, though not all, people. 

Reference: By Teri Robert, Medically reviewed by Claudia Chaves, MD; https://www.verywellhealth.com/injectable-or-nasal-dhe-for-treating-migraines-1719689 , consulted on july 1st,2019