Inclusion Criteria:

1. Written informed consent consistent with ICH/GCP and local legislation given prior to any study procedures.
2. Ability and willingness to comply with study treatment regimen and to attend study assessments.
3. Male or female out-patients aged 18-80 years.
4. Diagnosis of idiopathic RLS according to the clinical RLS criteria of the IRLSSG
5. RLS rating scale for severity total score >15.
6. RLS symptoms present at least 2 to 3 days per week during the last 3 months.

Exclusion Criteria:

1. Concomitant or previous pharmacologically therapy of RLS as follows:

   • Any intake of levodopa within 5 days prior to baseline visit (V2)
   • Any intake of dopamine agonists within 14 days prior to baseline visit (V2)
2. Current treatment with medication or dietary supplements, which could significantly influence RLS symptoms,e.g. dopaminergic (other than levodopa or dopamine agonists) or anti-dopaminergic drugs, non-selective MAO inhibitors, sympathomimetics, neuroleptics, anti-depressants, hypnotics, any benzodiazepines, antiepileptics, opioids, clonidine, magnesium, ferrous salts, Folic acid, vitamin B12, antihistaminics, lithium, metoclopramide or Withdrawal symptoms caused by stopping any of the drugs above
3. Confirmed diagnose of diabetic nephropathy or clinically significant renal disease