Are migraineurs at increased risk of adverse drug responses? A meta-analytic comparison of topiramate-related adverse drug reactions in epilepsy and migraine.

To compare adverse drug reactions (ADRs) to topiramate in patients with migraine and patients with epilepsy, we systematically reviewed all published randomized controlled trials (RCTs) that compare topiramate monotherapy in epilepsy and migraine. We included four epilepsy RCTs (N = 1,179 patients; vs. active comparators) and six migraine RCTs (N = 1,723 patients; vs. placebo). Behavioral ADRs and headache were found only in the case of epilepsy, whereas cognitive complaints and alteration of taste were found only in the case of migraine. The risk ratios (RRs) for paresthesia in migraine vs. epilepsy trials were 2.5 (99% confidence interval (CI): 1.66-3.77) for 50 mg, 2.7 (99% CI: 1.80-3.97) for 100 mg, and 3.0 (99% CI: 1.95-4.56) for 200 mg. For ADR-related dropouts, the RR was 2.5 (95% CI: 2.03-2.98) for 50 mg but no different for the other doses. We conclude that when treated with the same doses of topiramate, migraineurs show different ADRs than patients with epilepsy and are more likely to drop out because of ADRs.