Efficacy, safety and dose-response of pramipexole in Japanese patients with primary restless legs syndrome: randomized trial.
OBJECTIVE
To assess the safety and efficacy of pramipexole in Japanese patients with restless legs syndrome (RLS) and to investigate factors predictive of early treatment response.


METHODS
Patients with primary RLS and the International Restless Legs Syndrome Study Group rating scale (IRLS) total score of >15 were randomized to receive pramipexole 0.25, 0.5 or 0.75 mg/day for 6 weeks.


RESULTS
A total of 154 patients were recruited. Following treatment, the mean adjusted change in IRLS score in the 0.25, 0.5 and 0.75 mg/day groups was -12.3, -12.5 and -11.8, respectively. The proportion of IRLS responders at week 2, when all patients were receiving pramipexole at a dose of 0.25 mg/day, was 34.0-37.7%. At 6 weeks, when the patients were on 0.25, 0.5 or 0.75 mg/day, IRLS responders defined as those having a ≥50% reduction in IRLS score accounted for 60.4, 58.5 and 49.1%, respectively. Older age above the median value (≥55 years) and low IRLS score at baseline (<21.5 points) were significantly associated with early response to low-dose pramipexole therapy. The type and frequency of adverse events were consistent with the known safety profile for dopamine agonists in RLS.


CONCLUSIONS
Pramipexole at 0.25-0.75 mg/day is efficacious, safe and well tolerated in Japanese patients with primary RLS.
Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan. inoue@somnology.com
Yuichi
Y
Inoue
Kenji
K
Kuroda
Koichi
K
Hirata
Naohisa
N
Uchimura
Tatsuo
T
Kagimura
Tetsuo
T
Shimizu
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D052160:Benzothiazoles / Q000009:adverse effects / Q000627:therapeutic use*; D018491:Dopamine Agonists / Q000009:adverse effects / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077487:Pramipexole; D012148:Restless Legs Syndrome / Q000188:drug therapy*; D012720:Severity of Illness Index
D052160:Benzothiazoles; D018491:Dopamine Agonists; D000077487:Pramipexole