Opioids in the treatment of restless legs syndrome: pharmacological and clinical aspects.

Introduction: Restless legs syndrome (RLS) is a common neurologic sensory-motor disorder that can have a negative impact on sleep, quality of life and health. In patients affected by severe RLS, pharmacological treatment is mandatory.

Areas Covered: The present review is based on a search using PubMed from 1993 to 2016. It is focused on pharmacological and clinical aspects of opioids used for the treatment of RLS.

Expert Opinion: The drugs currently available for the treatment of RLS do not always allow to obtain an optimal control of symptoms, in particular, when utilised for long-term treatment. Opioids as monotherapy or add-on treatment should be considered when alternative satisfactory regimens are unavailable and the severity of symptoms warrants it. In a phase III trial oxycodone-naloxone prolonged-release (PR) demonstrated a significant and sustained effect on patients with severe RLS inadequately controlled by previous treatment. It was recently approved for the second-line symptomatic treatment of severe to very severe idiopathic RLS, after failure of dopaminergic treatment. Further studies are needed to evaluate if oxycodone-naloxone PR is equally efficacious as a first-line treatment. Moreover, long-term comparative studies between opioids, dopaminergic drugs and α-2-δ ligands are needed.