Dopaminergic treatment in idiopathic restless legs syndrome: effects on subjective sleepiness

To assess frequency and characteristics of excessive daytime sleepiness (EDS) in restless legs syndrome (RLS) and the evolution of EDS under different RLS therapies.

We analyzed data from the "Swiss RLS" study, which was conducted to compare treatment efficacy and safety of the dopamine agonist pramipexole (PPX) versus L-dopa/benserazide (L/B) in de novo patients with idiopathic RLS and performed as a randomized, double-dummy, comparative crossover trial. Primary outcome measure of the present study was the change in subjective sleepiness (as measured by Epworth sleepiness scale [ESS] score). There were 37 patients (21 women) included. Mean age was 56.6 years (range, 25-85 years), and mean body mass index was 24.6 (SD, ±3.5).

At baseline, EDS (as determined by an ESS score of >10) was found in 32% of the patients. Sleepy RLS patients were younger (P < 0.001) than non-sleepy patients. Pramipexole and L/B both were effective in the treatment of RLS symptoms (IRLS score, P < 0.001 and P = 0.002). Overall, ESS was reduced (main effect for "time", P = 0.02) independent from the dopaminergic substance. In 5 of 37 patients, ESS score deteriorated to greater than 10 under treatment (PPX = 3 patients, L/B = 2 patients). No sleep attack occurred.

Excessive daytime sleepiness is frequent in RLS patients. Dopaminergic treatment usually promotes wakefulness, but infrequently leads to daytime sleepiness.