Evidence Hub

A randomized trial of divalproex sodium extended-release tablets in migraine prophylaxis

Freitag FG, Collins SD, Carlson HA, Goldstein J, Saper J, Silberstein S, Mathew N, Winner PK et al.

Neurology, 2002

Abstract

OBJECTIVE: To evaluate the efficacy and safety of extended-release divalproex sodium compared with placebo in prophylactic monotherapy treatment of migraine headache.

METHODS: This was a double-blind, randomized, placebo-controlled, parallel-group study. Subjects with more than two migraine headache attacks during a 4-week baseline were randomly assigned in a 1:1 ratio at each center to receive either extended-release divalproex sodium or matching placebo once daily for 12 weeks. Subjects initiated treatment on 500 mg once daily for 1 week, and the dose was then increased to 1,000 mg once daily with an option, if intolerance occurred, to permanently decrease the dose to 500 mg during the second week. Reduction from baseline in 4-week migraine headache rate was the primary efficacy variable. Migraine headaches separated by a < 24-hour headache-free interval were counted as single migraines in calculating migraine headache rates. Tolerance and safety were also evaluated.

RESULTS: The mean reductions in 4-week migraine headache rate were 1.2 (from a baseline mean of 4.4) in the extended-release divalproex sodium group and 0.6 (from a baseline mean of 4.2) in the placebo group (p = 0.006); reductions with extended-release divalproex sodium were significantly greater than with placebo in all three 4-week segments of the treatment period. No significant differences were detected between treatment groups in either the overall incidence or in the incidence of any specific…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free