Open-label study of the long-term efficacy and safety of pramipexole in patients with Restless Legs Syndrome (extension of the PRELUDE study)

BACKGROUND AND OBJECTIVE: To demonstrate the long-term efficacy and safety of pramipexole for Restless Legs Syndrome (RLS) using physician and patient RLS ratings, along with subjective assays of sleep parameters, in a 26-week, open-label trial. PATIENTS AND METHODS: Among 107 Finnish adults with moderate to severe RLS, pramipexole initiated at 0.125 mg/day was titrated to a maximum 0.75 mg/day. Efficacy evaluations included the International RLS Study Group Rating Scale (IRLS), Patient Global Impression (PGI) scale, Clinical Global Impressions-Improvement (CGI-I) scale, Epworth Sleepiness Scale (ESS), and Short Form-36 (SF-36) Health Survey. Subjective Sleep Quality was assessed by patient ratings of sleep and morning tiredness. Safety was documented by Adverse Events reported in >5% of patients. RESULTS: The mean reduction in IRLS score was 73.5% (P<0.05). The IRLS responder rate, defined by score reduction of >or= 50%, was 81.3%. On the PGI scale, 89.7% of patients rated themselves as "very much" or "much" better. By CGI-I assessment, 94.8% of patients were considered either "very much" or "much" improved. Mean ESS score showed a modest but statistically significant reduction (P<0.05) within the normal range, indicating that long-term pramipexole did not increase daytime sleepiness. On the SF-36 all 8 domains showed improvement, 5 of them statistically significant (P<0.05) and 4 of these 5 (role-physical, bodily pain, vitality, and role-emotional) by >10 points on a 100-point scale. Subjective Sleep Quality also improved. The most frequent Adverse Events were influenza (17.8%), headache (15.0%), and fatigue (10.3%). CONCLUSION: Pramipexole is well tolerated and effective for long-term treatment of RLS.