Pramipexole: in restless legs syndrome

Pramipexole is an oral, non-ergoline dopamine agonist with selectivity for the dopamine D(3) receptor, which was recently approved in the EU and the US for the treatment of idiopathic restless legs syndrome (RLS) in adults. In a polysomnographic study, pramipexole 0.125, 0.25, 0.50 or 0.75 mg once daily for 3 weeks significantly reduced from baseline the periodic limb movement index compared with placebo (-27 to -53 vs -3). Pramipexole at a median dosage of 0.35 mg/day for 6 weeks significantly reduced from baseline the mean International RLS Study Group rating scale (IRLS) score compared with placebo (-12.4 vs -6.1) and produced a significantly higher response ('much improved' or 'very much improved') rate (63% vs 33%) according to the Clinical Global Impressions-Improvement (CGI-I) scale. In a controlled-withdrawal study in which responders to pramipexole following 6 months' therapy were randomised to pramipexole or placebo for 12 weeks, significantly less pramipexole than placebo recipients reached the target event of predefined worsening of symptoms (21% vs 86%). Treatment with pramipexole 0.25, 0.50 or 0.75 mg once daily for 12 weeks significantly reduced IRLS scores from baseline values (-13 to -14 vs -9) and produced significantly higher proportions of CGI-I responders (68-75% vs 51%) compared with placebo. Pramipexole was generally well tolerated, with most adverse events being transient and of mild to moderate severity.