Migraineurs treated with topiramate often experience adverse effects, such as paresthesia, fatigue, memory difficulty, or taste perversion. To investigate correlations between side effects and drug efficacy, we analyzed for these in 133 migraineurs treated with topiramate (100 mg/day). A 4-week baseline screening phase preceded a 4-week titration period and a 20-week maintenance phase. A total of 118 patients were evaluated at 3 months and 89 patients at 6 months. Patients who developed paresthesia (n = 73) showed lower headache days than those who did not (n = 60) (P = 0.026 at 3 months, P = 0.002 at 6 months), and had a higher responder rate (3 months, 57.5% and 6 months, 65.8%) than those who did not develop paresthesia (3 months, 38.3% and 6 months, 41.7%). Moreover, retrospective analysis of patients that dropped out showed no survival bias between paresthesia and headache improvement. Other adverse effects were not found to correlate with drug efficacy. This study suggests that the development of paresthesia predicts a favorable response to topiramate in migraine prophylaxis.

Levetiracetam does not appear to be efficacious in patients with oromandibular or cranial dystonia.