Patients with normal (creatinine clearance CrCl > 80 ml/ min), mild (CrCl 60 - 80 ml/ min), moderate (CrCl 30 - < 60 ml/ min), or severe (< 30 ml/ min) renal impairment received hydroxycarbamide as a single dose of 15 mg/ kg b. w. by using 200 mg, 300 mg, or 400 mg capsules.