Intravenous Iron in the Management of Drug-resistant Restless Legs syndromeI

The pathophysiology of restless legs syndrome (RLS) is not well understood: it is thought to involve intracerebral iron deficiency and dopaminergic dysregulation. This study aims to evaluate the use of intravenous ferric carboxymaltose in patients with restless legs syndrome (RLS). This study plans to include individuals with RLS, who will be divided into two groups: * One group will receive intravenous iron immediately after the baseline polysomnography * The second group will receive intravenous iron 3 months after randomization. In total, participants will be followed for 6 months, during which time they will be required to complete questionnaires regularly, undergo blood draws, and have two polysomnography tests.