One-third of the five million headache patients who present to US Emergency Departments (ED) annually have a migraine headache. The anti-emetic dopamine receptor antagonists have proven efficacy for migraines, are at least as well-tolerated as triptans, and enjoy wide-spread use in North American EDs. However, it is not yet clear which medication within this class and which dosage is optimal. Therefore, we propose a randomized clinical trial to compare the efficacy and tolerability of two standard medications for migraine.