The treatment of restless legs syndrome with intravenous iron dextran

BACKGROUND AND PURPOSE: To evaluate the safety and efficacy of a single 1000 mg iron infusion in treating Restless Legs Syndrome (RLS). PATIENTS AND METHODS: A single 1000 mg intravenous (IV) [Am J Med Sci 31 (1999) 213] infusion of iron dextran was evaluated in an open-label study. Primary outcomes of efficacy were symptom severity assessed by global rating scale and periodic leg movements in sleep (PLMS) at 2 weeks post-infusion. Secondary outcomes included total sleep time (TST), hours/day of RLS symptoms, and changes in magnetic resonance imaging (MRI)-determined iron concentrations in the substantia nigra. Primary safety measures were reported adverse events and monthly serum ferritin levels. RESULTS: IV iron therapy significantly improved the mean global RLS symptom severity, TST, hours with RLS symptoms and PLMS, but on an individual basis failed to produce any response in 3 of the 10 subjects who were fully treated. Brian iron concentrations at 2 weeks post-infusion as determined by MRI were increased in the substantia nigra and prefrontal cortex. Serum ferritin levels showed a greater than predicted rapid linear decrease. Side effects were mild, except in one subject who developed an acute allergic reaction. CONCLUSIONS: The results in this study provide valuable information for future studies, but the efficacy and safety of IV iron treatment for RLS remain to be established in double-blind studies. The serum ferritin results suggest that greater than expected iron loss occurs after IV iron loading.