The treatment of restless legs syndrome with intravenous iron dextran

To evaluate the safety and efficacy of a single 1000 mg iron infusion in treating Restless Legs Syndrome (RLS).

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.

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.

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.