Randomized trial of pramipexole for patients with restless legs syndrome (RLS) and RLS-related impairment of mood.

OBJECTIVES: Patients with restless legs syndrome (RLS) have an elevated prevalence of mood disorders compared with the general population. We investigated the change of RLS-related mood impairment during treatment of RLS with pramipexole, a dopamine D(3)/D(2) agonist.

METHODS: Adults with moderate to very severe RLS were enrolled in a 12-week, double-blind, placebo-controlled Phase IV pramipexole trial. A moderate to very severe RLS-related mood disturbance at baseline (score ≥2 on Item 10 of the International RLS Study Group Rating Scale [IRLS]) was also required. Pramipexole (0.125 to 0.75 mg once daily) was flexibly titrated over the first 4 weeks.

RESULTS: The intent-to-treat population comprised 199 patients on placebo and 203 on pramipexole. At week 12, adjusted mean total-score changes on IRLS were -14.2±0.7 for pramipexole and -8.1±0.7 for placebo (p<0.0001), and on the Beck Depression Inventory version II, -7.3±0.4 for pramipexole and -5.8±0.5 for placebo (p=0.0199). For IRLS item 10, the 12-week responder rate (reduction to no or mild mood disturbance) was 75.9% for pramipexole and 57.3% for placebo (p<0.0001). Study withdrawal rates were higher for placebo (20.5%) than for pramipexole (12.8%).

CONCLUSIONS: In patients with RLS-related mood disturbance, pramipexole improved RLS while also improving RLS-related mood impairment. Tolerability of pramipexole was similar to that in previous studies.