Loss of efficacy and augmentation are two main treatment failures after a long course of treatment of RLS. The probable reasons of them might be the natural worsening of RLS symptoms over time or compensatory response of CNS to chronic drug treatment (Mackie and Winkelman, 2015). Iron deficiency should be treated with iron supplement. Both of the intravenous and oral iron formulations are proved to be effective in some RLS patients (Trotti et al., 2012; Hornyak et al., 2014). Further study about effect of iron therapy in all RLS patients or only a certain type of RLS remains to be investigated.