A Randomized, Double-Blind Placebo-Controlled Trial of Iron in Restless Legs Syndrome

Abstract

BACKGROUND: Previous open-label trials have shown iron to be efficacious in the treatment of restless legs syndrome. We performed a randomized, double-blind, placebo-controlled trial of iron sulfate. METHODS: Twenty-eight patients were randomized to receive either ferrous sulfate 325 mg b.i.d. or placebo for 12 weeks. The primary outcome measure was the dichotomous variable of improvement or no improvement in average quality of sleep as recorded by a visual analog scale nightly over a 2-week period, comparing a pretreatment 2-week baseline to weeks 13-14. Secondary outcome measures included a comparison of the quality of sleep as measured by a visual analog scale, effect of restless legs syndrome on life as a whole as measured by a different visual analog scale, and the percentage of nights patients were symptomatic. RESULTS: No significant differences were noted between iron and placebo groups for both primary and secondary outcome measures. Responders taking iron did have a significant increase in their iron saturation compared to nonresponders taking iron. CONCLUSIONS: Iron sulfate does not appear to be an effective empiric treatment for restless legs syndrome.