An Open-label Study of the Safety and Efficacy of Topiramate for Migraine Prophylaxis: Extension Study to CAPSS-277

Migraine headaches can be disabling and can interfere with work and a person's quality of life. Preventing these headaches before they start is the best option. Topiramate, an anti-seizure medication, has been shown to help prevent migraine headaches from occurring. This is an open-label study that is an extension of a previous study (CAPSS-277) comparing topiramate and amitriptyline in migraine prevention. It includes patients who completed the previous study and elected to enter open label treatment with topiramate. The study will involve a 4-week Blinded Transition Phase during which patients will be titrated up to a daily topiramate dose of 100 milligrams (or the maximum tolerated dose, whichever is less). Then there will be a 12-week Open-Label Maintenance Phase during which the topiramate dose may be adjusted according to effectiveness and tolerance, but not to exceed a daily dose of 400 milligrams. While on topiramate, patients will record daily entries in their headache records. Patients will be asked questions to help assess their quality of life. Patients will also have physical examinations and laboratory tests performed during the study. The objective of this study is to evaluate the long-term safety and effectiveness of topiramate for the prevention of migraine headaches.

Topiramate oral tablets, 25 milligrams per tablet, will be given in the morning and evening to a dose not to exceed 400 milligrams per day or to the maximum tolerated dose, whichever is less