Subjects will have 7 study visits. Routine laboratory studies and a pregnancy test will be performed at enrollment and week 20. Abnormal kidney or liver function will exclude subjects. Pregnancy will exclude subjects. General and neurologic examinations will be performed during 3 of the 7 visits. At each visit, subjects will receive medication for the period until the next visit. A headache diary will be used for the trial. For every day that the subject has a headache of any type, she or he will record headache characteristics, associated features, and medications used.