PITTSBURGH — Topiramate appears to be a good choice for preventing pediatric migraine, including basilar migraine, researchers reported at the annual meeting of the Child Neurology Society.
The drug was approved for treatment of adult migraine in 2004, and is used off label for pediatric migraine, said Dr. Marcus Cruz of St. Christopher's Hospital for Children, Philadelphia. “However, the availability of sufficient data to support the effectiveness, tolerability, and adequate dose is scarce and not yet well supported.”
Dr. Cruz retrospectively examined the use of topiramate as a migraine prophylactic in 37 children (mean age 14 years). Most of the group (81%) experienced migraine without aura; 11% had migraine with aura, and the rest of the children had abdominal, ophthalmoplegic, or catamenial migraine.
For 21 patients, topiramate was the first-line prophylactic therapy; for the remainder of the group, it was an add-on drug.
Most of the children (65%) had an excellent or good response to topiramate. Before treatment, the children had an average of 15 headaches per month; after treatment, that number decreased to about 3 per month.
Eight children had side effects, including cognitive effects (four), drowsiness (three), and paresthesias (one). All four patients who experienced cognitive side effects were switched to another medication. There was a direct correlation between dosage and side effects, Dr. Cruz noted. Children taking more than 2 mg/kg per day were significantly more likely to have adverse effects than were children taking less than 2 mg/kg per day.
“We found a significant reduction in headaches beginning at a mean of 1.7 mg/kg per day, with the most effective dose being right at 2 mg/kg per day,” he said. “When the patients started taking more of the drug, they only had a 30% chance of having more improvement in headache control, but they were more likely to get side effects.” He did not see weight loss in this group, perhaps because the doses were smaller than those usually given to patients with seizure disorders.
Topiramate is also effective in preventing basilar-type migraine in children, said Dr. Donald Lewis, of Eastern Virginia Medical School, Norfolk. In a small, parallel-group study, the drug significantly reduced the total number of headache days per month.
Basilar migraine affects up to 19% of children with migraine, and is characterized by episodes of intense dizziness, vertigo, visual disturbances, ataxia, and diplopia, followed by pain. Dr. Lewis' study included 14 children aged 6–18 years who received either 25 mg or 100 mg of topiramate per day.
At baseline, the children had a median of five migraines per month and a median PedMIDAS migraine assessment score of 33, indicating moderate disability. Most of the children reported their pain level as severe or excruciating.
After reaching their target dosage and entering a maintenance phase, 100% of children in the 25-mg/day group and 71% of those in the 100-mg/day group experienced a reduction in all migraine days of at least 50% per month (a median decrease from 4.5 days to 1.5 days), Dr. Lewis said.
The drug also significantly reduced the number of days with basilar migraines in each group from a median of 3 days to a median of 0.6 days per month. Neither dosage had a significant effect on the duration or intensity of any migraines that occurred during treatment, however. The 100-mg dose was not significantly more effective than the 25-mg dose.
Adverse events occurred in five children in each dosage group, with a total of 21 events in the 25-mg group and 14 in the 100-mg group. Of these, only 15 were probably related to the study drug, and none was considered serious. Adverse events included paresthesias, nausea, fatigue, and cognitive symptoms.
The study was supported by a research grant from Ortho-McNeil Neurologics Inc.