Study objectives: To evaluate the efficacy and the safety of cabergoline, a dopamine-receptor agonist with a long half-life, in restless legs syndrome (RLS).
Design: A 2 month, single blind, open labeled clinical trial. Patients were evaluated with polysomnography at baseline (B), following 1 week of placebo (T0), and after 1 week (T1) and 2 months (T2) of cabergoline treatment. The clinical global impression was assessed using International RLS Study Group Rating Scale and nocturnal actigraphy.
Setting: Sleep Disorders Center.
Patients: Twelve patients with moderate to severe RLS (mean age 56.6 years) who were naive to treatment with dopaminergic agents.
Interventions: Upward titration of cabergoline (from 0.5 mg to 2 mg) in a single evening dose.
Measurements and results: Ten patients completed the study (mean dose, 1.1 mg), and all showed an improvement of RLS symptoms. The results from the International RLS Study Group Rating Scale showed similarities between B (24.3+/-2.9) and T0 (23.1+/-5.9; P=0.6), with significant improvement at T1 (12.5+/-6.0; P=0.01 vs B and T0) and T2 (9.8+/-6.9; P=0.001 vs B and P=0.005 vs T0). The mean nocturnal activity value measured by actigraphy during week 1 decreased from T0 (19.8+/-9.3) to T1 (13.6+/-6.4) and dropped significantly at T2 (8.5+/-5.3; P=0.05). Nine patients continued the treatment up to 12 months with consistent efficacy, few side effects, and no augmentation.
Conclusions: Low doses of cabergoline showed effectiveness and safety in patients with moderate to severe RLS, with no appearance of augmentation phenomenon. Double blind, crossover, polysomnographic studies are necessary to confirm this preliminary data.