Factors affecting the efficacy of pramipexole in patients with restless legs syndrome.

Dopamine agonists, particularly nonergot dopamine agonists such as pramipexole, have become the mainstay of therapy for patients with symptoms of restless legs syndrome (RLS). This study was designed to evaluate the factors affecting the efficacy of pramipexole in patients with RLS. Fifty-nine eligible RLS patients referred to neurology clinic of Rasoul-e-Akram Hospital (Tehran, Iran) were recruited in this study. All of the patients received an oral dose of 0.18 mg pramipexole. The severity of RLS symptoms were evaluated including sleep disorder, symptomatic days per week and symptomatic hours per day, both at the beginning and at the end of follow-up time. Different baseline and follow-up variables were also recorded and their relationships with the outcomes were assessed. The mean severity values of different symptoms significantly decreased after treatment with pramipexole (P<0.001). Female gender (P<0.05) and duration of treatment (P<0.05) were significant factors to achieve >50% reduction in symptomatic days per week and symptomatic hours per day. Moreover, the cutoff point of 3.5 mo for duration of treatment could potentially differentiate >50% reduction in severity of sleep disorder from the ones with <50% reduction with sensitivity and specificity of 56.8% and 78.6%, respectively. Our findings show that female gender and duration of treatment were the factors affecting the effectiveness of pramipexole in RLS patients. If tolerated by the patients, a longer duration of treatment with pramipexole is more effective in RLS.