A controlled study of additional sr-L-dopa in L-dopa-responsive restless legs syndrome with late-night symptoms

To investigate whether a combination treatment of regular-release levodopa (rr-L-dopa) and sustained-release levodopa (sr-L-dopa) compared with monotherapy of rr-L-dopa improves sleep quality and reduces periodic limb movements (PLM) in patients with restless legs syndrome (RLS) and problems with maintaining sleep.

Reappearance of RLS symptoms during the second half of the night while being treated with rr-L-dopa is a common problem in the treatment of sleep disturbances caused by RLS.

A randomized, controlled, double-blind crossover trial was undertaken. Eligible patients fulfilled the diagnostic criteria of the International RLS Study Group, and met an actigraphically confirmed higher number of PLM per hour time in bed (PLM index) during the second half compared with the first half of the night under treatment with rr-L-dopa. During the crossover periods the patients received 100 to 200 mg rr-L-dopa plus either placebo or 100 to 200 mg sr-L-dopa at bedtime for 4 weeks each period.

Thirty patients with RLS (11 men and 19 women) were assessed by actigraphy and subjective sleep quality, and showed a significant improvement in PLM index (p < 0.0001), in "time in bed without movements" (p < 0.0001), and in subjective sleep quality (p < 0.001). Eight of 30 patients reported an altered pattern of RLS symptoms, characterized by a time shift of RLS symptoms into the afternoon or evening, five of these during monotherapy with rr-L-dopa.

A combination therapy of rr-L-dopa and sr-L-dopa is better than monotherapy with rr-L-dopa in reducing the frequency of PLM and problems maintaining sleep, even in patients who are severely affected.