The purpose of this study is to compare the effectiveness and safety of two treatment regimens in preventing migraines. The antidepressant amitriptyline has been used successfully to prevent migraine headaches.

People who suffer from migraines have many prescription medications to choose from, both to treat the migraine and to prevent it from starting. However, many patients have not had success in finding the drug that helps them best. Amitriptyline, an antidepressant, has been used successfully for many years to prevent migraine headaches. This study will compare the effectiveness of amitriptyline with the effectiveness of topiramate, an anti-seizure drug, in preventing migraines. The safety of both drugs will also be assessed. The objective of the study is to demonstrate that topiramate will be at least as effective as amitriptyline in preventing migraines. During the first 4 weeks of the study, topiramate or amitriptyline will be increased by 25 mg per week up to a total dose of 100 mg per day or up to the maximum tolerated dose, whichever is less. Treatment will continue at 100 mg per day for 22 weeks.

Inclusion Criteria:

• Migraine headache for at least 6 months, with 3 to 12 headaches a month for the previous 3 months
• no more than 15 headache days in the previous month before study start
• no heart rhythm problems or neurologic problems
• women must not be pregnant and must use birth control

Exclusion Criteria:

• Cannot have failed at least 2 previous trials of migraine prevention drugs
• cannot have failed a previous trial of topiramate or amitriptyline
• no cluster headaches
• no migraine with aura without headache
• no pain that is worse than the migraine pain