The purpose of this study is to assess the safety and efficacy of topiramate as compared to placebo in preventing migraines in children.

Pediatric migraine headache is a common cause of severe recurring headaches in children, especially children between the ages of 5 and 15 years. These headaches can be disabling and tend to interfere with a child's daily activities, such as going to school or playing with friends. Because pediatric migraine children tend to be misdiagnosed, they are often not treated effectively. Topiramate, an anti-seizure medication, has been shown to prevent migraines in adults, and it has been approved to treat seizures in children as young as 2 years of age as add-on treatment (used with another drug) and also can be used alone (monotherapy) in children as young as 10 years old. Since topiramate has already been studied in children, information about its safety in children is available. In this study, children with migraine headaches will be identified. It is not necessary for the child to have the migraine aura (having blurry vision; seeing flashing lights) to be included in this study. This is a randomized, double-blind, placebo-controlled study of Topiramate (or placebo) given for 4 to 5 months. An optional 3-month open-label extension (topiramate only; no placebo) will follow. The objective of the study is to demonstrate that topiramate is effective and safe when used to prevent migraine headaches (with or without aura) in children. Safety will be assessed throughout the study.

Topiramate sprinkle capsules (or placebo), starting at 15 milligrams per day for 1st week; increased to 30 milligrams per day for week 2; increased to 50 milligrams (in tablets) per day in week 3, then adjusted as needed to 2 to 3 milligrams/kilogram/day for the rest of study (140 days total).

Inclusion Criteria:

• Children who have had several attacks of headaches that meet the International Headache Society Classification of pediatric migraine with or without aura (for example, headache lasts up to 48 hours, has a throbbing quality, is accompanied by nausea or sensitivity to light, is made worse by physical activity)
• Average of 3 to 10 migraine days per month for previous 3 months
• Weighs more than 20 kilograms (44 pounds)
• Able to swallow a tablet whole (without crushing it)

Exclusion Criteria:

• Took topiramate previously to prevent migraines but it was not effective
• Had to stop taking topiramate because of side effects
• Presence of cluster headaches, migraine aura without headache
• Had taken any medications for migraine prevention within 2 weeks before study start
• Presence of active liver disease or abnormal kidney function