But one expert notes problems with manufacturing, unreliable delivery of the drug
FRIDAY, May 30 (HealthDay News) -- Skin patches that contain the drug rotigotine help relieve restless legs syndrome (RLS), according to a German study.
Dopaminergic drugs -- which stimulate the body's dopamine system -- are currently used as a first-line treatment for RLS, and rotigotine is already used to treat Parkinson's disease. This study of 458 people with moderate to severe RLS examined the efficacy of rotigotine skin patches.
The patients were randomly assigned to apply skin patches with 1 milligrams of rotigotine (115 patients), 2 milligrams (112), or 3 milligrams (114) once a day for six months. A fourth group of 117 patients received a placebo.
The patients were assessed using the International Restless Leg Syndrome study group severity rating scale (IRLS) and the clinical global impressions (CGI) item 1 score, which measures severity of symptoms. At the start of the study, the patients' average IRLS score was 28.1, and their average CGI item 1 score was four or more.
At the end of the study, mean changes in IRLS score were: -13.7 in the 1 mg group; -16.2 in the 2 mg group; -16.8 in the 3 mg group; and -8.6 in the placebo group. Changes in the CGI item 1 score were: -2.09 in the 1 mg group; -2.41 in the 2 mg group; -2.55 in the 3 mg group; and -1.34 in the placebo group.
Of the 341 patients who used the rotigotine skin patches, 145 (43 percent) experienced skin reactions (mostly mild or moderate), compared to two of 117 (2 percent) of those who received the placebo.
Ten patients suffered serious side effects related to rotigotine: elevation of liver enzymes (1 patient); worsening of tinnitus (1); non-response to anticoagulation (1); electrocardiogram changes (1); and skin patch application site reactions (6). All the skin reactions resolved within a short time after the patch was removed.
"The results of this 6-month trial indicate that transdermal delivery of low doses of rotigotine for 24 h per day are more effective than placebo at relieving symptoms of RLS in patients who are moderately to severely affected. This trial, together with a pilot study and dose-finding trial, suggest that, despite differences in treatment duration and other design features, there exists a clear therapeutic window in terms of dose of rotigotine to treat restless legs syndrome between 1 mg over 24 h to 3 mg over 24 h," the study authors wrote.
The study was published online in The Lancet Neurology and was expected to be in the July print issue of the journal.
"The introduction of a patch with a constant delivery of a dopamine agonist is a welcome addition to the armamentarium. Unfortunately, the rotigotine patch has been temporarily withdrawn from the U.S. market because of problems with manufacturing and the unreliable delivery of the drug," Dr. Kapil Sethi, of the Medical College of Georgia, wrote in an accompanying commentary.
"RLS causes significant discomfort and adversely affects the quality of life of patients. Whether it has more ominous consequences is unclear. A recent study showed that RLS is associated with a greater risk of cardiovascular disease, particularly in patients with greater frequency or severity of RLS symptoms. Whether treatment of RLS will reduce this risk is unknown, and further studies should help answer this question," Sethi wrote.
The U.S. National Institute of Neurological Disorders and Stroke has more about restless legs syndrome.
-- Robert Preidt
SOURCE: The Lancet Neurology, news release, May 31, 2008
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