Effects of Switching from Allopurinol to Febuxostat in Chronic Kidney Disease Patients

Febuxostat, a new xanthine oxidase (XO) inhibitor, could become the standard for managing uric acid levels in patients with chronic kidney disease (CKD). However, little has been reported regarding patients with severe renal impairment. Further, the conversion rate for switching patients from allopurinol to febuxostat remains unknown. We studied 65 CKD patients being administered allopurinol for hyperuricemia and then switched them to febuxostat at a conversion ratio of 100 mg allopurinol: 10 mg febuxostat. Serum uric acid and creatinine levels were measured before and 4–8 weeks after the switch. Sixty-three patients remained after excluding those who had discontinued treatment. There was no significant difference in serum uric acid and creatinine levels before and after the switch. Further, no significant differences were observed in serum uric acid levels before and after the switch when patients were stratified into diabetic and nondiabetic groups or when classified per gender. We divided patients into G1–G3b and G4–G5 groups depending on the stage of CKD; there were no significant differences in the G1–G3b group after the switch, but there was a significant decrease in serum uric acid levels in the G4–G5 group (p < 0.05). We demonstrated that 100 mg allopurinol and 10 mg febuxostat had equivalent hypouricemic effects in CKD patients and that these drugs did not affect serum creatinine levels. Thus, 10 mg febuxostat may have greater hypouricemic effects in patients with advanced CKD.