Efficacy and safety of pramipexole in Japanese patients with primary restless legs syndrome: A polysomnographic randomized, double-blind, placebo-controlled study

Abstract

Objective: To evaluate the efficacy of pramipexole on polysomnographic measures, patient ratings and a clinical rating in Japanese patients with primary restless legs syndrome (RLS).

Methods: Patients with moderate to severe RLS having periodic limb movements in bed index (PLMI)>or=5 were randomly assigned to receive pramipexole or placebo in a 6-week, double-blind, placebo-controlled study with forced titration from 0.125 to 0.75mg/day. Both polysomnography (PSG) and the suggested immobilization test (SIT) were performed at baseline and 6weeks after starting treatment.

Results: The analysis of covariance of log-transformed PLMI showed that the adjusted means at the end of study were significantly smaller in the pramipexole group than in the placebo group (p=0.0019). In all patients, variables on SIT did not show any differences between the two groups, whereas a significant improvement was shown in the pramipexole group compared with the placebo group for patients with a SIT-PLM index at baseline >or=15. Pramipexole group showed a significant reduction in the International Restless Legs Syndrome Study Group rating scale (IRLS; p=0.0005), a significant improvement in both Patient Global Impression (PGI; p<0.0001) and Clinical Global Impressions (CGI-I; p=0.0488), and a significantly greater mean reduction in the Pittsburgh Sleep Quality Index (PSQI; p=0.0016), when compared with those of placebo group at week 6.

Conclusions: Pramipexole is highly efficacious in the reduction of PLMI and in the improvement of subjective severity of RLS and subjective sleep disturbance caused by the disorder.