Post-marketing Study of Gabapentin Enacarbil to Evaluate the Effect in Restless Leg Syndrome (RLS) Patients With Moderate Renal Impairment

- Patients who have been diagnosed with restless legs syndrome (RLS) according to the international RLS Study Group Diagnostic Criteria

- Patients whose score is 15 or greater on the International RLS (IRLS) Rating Scale on the first day of the pre-observation period.

- Patients whose creatinine clearance level at the first day of pre-observation period is ≥30 mL/min to <60mL/min estimated by Cockcroft-Gaul t equation

- Patients who provide written consent

- Patients with sleep disorder such as sleep apnea syndrome, which affects the RLS evaluation

- Patients with history of augmentation and treatment rebound of RLS symptoms when using dopamine agonis

- Patients with neuropathy and movement disorder (diabetic neuropathy, Parkinson's disease, multiple sclerosis, dyskinesia, rheumatoid arthritis etc)

- Patients with uncontrolled diabetes [HbA1c>7.5% (NGSP value), in the past six months], iron deficiency anemia, or drug administration of hypnotic sedatives.

- Patients who attempted suicide within six months prior to the consent obtained, or who have been diagnosed as a suicide risk by investigator or sub-investigator

- Patients with moderate or severe depression

- Patients with alcohol dependence or drug intoxication or who have a history of abuse or drug dependence in the past one year

- Patients whose job is shift work, professional driver, or engaging in hazardous activities such as operating machinery

- Patients with history of hypersensitivity to gabapentin

- Patients who have experience to participate in other post-marketing clinical studies or clinical trials within 12 weeks prior to the start of pre-observation

- Others: patients who are concluded to be ineligible by an investigator or sub-investigator as ineligible