Prophylactic sodium valproate therapy in patients with drug-resistant migraine

We assessed the efficacy of sodium valproate as a prophylactic agent in migraine headache. A prospective randomized study was conducted in adult patients who previously derived no significant benefit from most conventional prophylactic therapy for migraine. Twenty-seven patients with a diagnosis of migraine with aura or migraine without aura from a headache clinic received low dose sodium valproate for 3 months. Response to therapy was deifined as 50% or greater reduction in the frequency of headache. Plasma drug level monitoring helped to identify four noncompliers who were excluded from the study. Seventeen (71%) patients observed improvement within 4-6 weeks of medication and remained well for 12 weeks. They were further followed up for 12-24 months. Two patients for side effects and I for nondrug-related problems were withdrawn from follow-up study Twelve patients (60%) maintained their response for 12 months or longer Clinical improvement (percentage reduction in the frequency of migraine attacks) correlated inversely with the plasma drug levels at 13-24 months and daily dose of valproate, among the responders, suggestive of a possible therapeutic window. In other words, patients who do not respond to low dose valproate are unlikely to benefit from further increase in dosage, (C) 1998 Prous Science. All rights reserved.