Long-term use of pramipexole in the management of restless legs syndrome.

OBJECTIVE Few studies have examined the long-term use of dopamine agonists for restless legs syndrome (RLS). We report a cohort study of 50 patients initially prescribed pramipexole between 1998 and 2002. The objective was to determine duration of treatment, long-term efficacy, development of side effects and augmentation over an extended period. METHODS We performed a long-term analysis on a previously reported group of patients initially followed for a mean of 27.2 months. Data were collected using retrospective chart reviews, written surveys and systematic telephone interviews. RESULTS Pramipexole was used for a mean of 8 years (range 0.6-12 years). Nine (18%) discontinued pramipexole because of poor efficacy (four), impulse control disorders (ICD) (two), augmentation (one) and resolved symptoms (two). Pramipexole was reported completely effective in 40% (compared to 67% at the end of the initial study), partially effective in 58% and ineffective in 2%. The median daily dose increased from 0.38 mg after initial stabilization to 1.0mg at the end of the study. As many as 74% of patients experienced side effects. A total of 56% reported daytime sleepiness including 10% reporting sleep attacks while driving and 10% developed ICDs. Augmentation developed in 42% of patients, after a mean of 16.5 months, and no later than 4.1 years after commencing treatment. A total of 28% needed additional non-dopaminergic medications. CONCLUSION The efficacy of pramipexole dropped with time, with increase in dose and addition of other agents, although the majority of patients remained on the drug. Problems included the development of augmentation within the first 4 years of therapy and side effects such as sleepiness increasing with time and the development of ICDs. The study highlights the need for further research into alternative non-dopaminergic treatments for RLS.