<qa>  What is the main reason subjects are willing to come to the study site when they have onset- Subjects are willing to come to the study site when heshe has onset of the headache of migraine to receive an intravenous dose of study medication and is willing to remain in the investigators clinic for at least 2 hours after the intravenous dose for collection of study data Subject is discharged to home after 2 hour post-dose evaluations are completed. 