Twenty-two patients, attending the Neurology outpatients of a tertiary care hospital and having at least a 6-month history of migraine with 3-12 attacks per months were enrolled for the study. The patients were recruited if they met the International Headache Society (IHS) criteria for diagnosis of migraine and were excluded if they experienced headache other than migraine, had late onset migraine or renal stones. Patients were also excluded if they had more than 15 attacks of migraine per month or were given topiramate for any other indications. A wash out period of 14 days was given during which rescue analgesics of NSAID class (e.g. ibuprofen 6mg/kg) was allowed.

Patients were prescribed tablet topiramate 15 mg/day and titrated over 8 weeks to 2 mg/kg or maximum tolerated dose, whichever was less. The patients were asked to report after third month. A responder was defined as a patient who achieved at least 50% reduction in monthly migraine attacks.

Headache severity was graded on a 4 point scale ranging from grade 3, severe, requiring rest in bed; grade 2 moderate reduced capacity; grade 1, mild but not interfering with working capacity; and, grade 0, none, able to work or function normally. The primary efficacy was judged by reduction in mean migraine frequency across 12-weeks study period. Baseline (0 day) and endpoint assessment (3 months) of the patients was done. Headache Intensity was rated on a 10-point Visual Analogue Scale where 0 represented no pain and 10 represented the most severe pain (Table I). Patients were asked to keep a daily diary of their migraine attacks and associated symptoms like nausea, vomiting and aura. Safety was assessed by observing the treatment emergent side effects. Patients and parents were encouraged to report any treatment related side effects or report any new symptom following drug intake.

TABLE I	Severity of Migraine Symptoms Before and After Topiramate (n=18)  

Baseline (0 day) routine hematological investigations (total and differential leukocyte count), urine analysis (microscopic), blood urea, creatinine, and liver function tests were done. Fisher Exact test and Chi square tests were used for statistical analysis with P<0.05 considered as significant.

Four patients were lost to follow up. Fourteen out of 18 patients (M:F 4:14 mean age 11.2 years, mean migraine duration: 1.2 years) had statistically significant reduction in severity of headache and migraine associated symptoms. Side effects reported were mild and included anorexia in 2, and paresthesia and impaired concentration in 1 each. None of the patient opted out of the study due to side effects.

In the present study, 77.7% of 18 children had significant pain relief, and reduction in severity of headache and migraine associated symptoms. In a prospective case series of 24 children diagnosed with migraine refractory to prophylactics and treated for 4 months with topiramate as the only prophylactic drug [7], the drug was found to be safe and effective. In another similar study [8] severity and duration of headache were also reduced. Headache disability improved, with a reduction of PedMIDAS scores.

This is consistent with earlier studies [7,9,10]. We used the maintenance dose of 2 mg/kg/day as earlier described [10]. These authors reported a 75% of greater reduction in mean migraine frequency in 32% of the 160 children studied. Higher response rate in our study could be due to small sample size or because we defined a responder as the patient having 50% or more reduction.

Topiramate was found to be a safe, efficacious and well tolerated drug in migraine prophylaxis in children.

Funding: None; Competing interests: None stated.

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