Pharmacotherapy of Restless Legs Syndrome with Pramipexole

Abstract

The dopamine agonist pramipexole (PRA) ((S)-2-Amino-4,5,6,7-tetrahydro-6-(propylamino) benzothiazole dihydrochloride; molecular formula C10H17N3S⋅2(HCl), is a D3 selective compound, approved in 1997 for the treatment of Parkinson disease and in 2006 for that of idiopathic restless legs syndrome (RLS). Because of its tolerability, safety and half-life, PRA is favored over levodopa and on the other ergot derivate dopamine agonists, and it is considered nowadays one of the first choices in the therapy of RLS. PRA is rapidly and completely absorbed after oral administration, its protein binding is around 15%, it is almost unaffected by hepatic metabolism and excreted by urine unchanged. PRA has a linear pharmacokinetics, with a half-life ranging between 8 and 14 hours. Double-blind, placebo-controlled studies demonstrated that PRA, even at low dosages and since the first nights of administration, is significantly effective on the typical sensitive symptoms of RLS, on the periodic leg movements during sleep, and in improving the quality of life of patients with RLS. A subjective improvement of sleep quality is usually also reported by the patients, but the polysomnographic assessment gave less solid results on objective sleep parameters. The most common PRA related side effects include headache, nausea and orthostatic hypotension. Data on the long-term therapy of PRA in RLS, and on the efficacy of PRA in symptomatic forms of RLS are warranted to better delineate the role of PRA in RLS treatment.