-80 mL per min), moderate (Cl 30-49 mL per min) or severe renal impairment (Cl 10-29 mL per min), the C of febuxostat did not change relative to subjects with normal renal function (Cl greater than 80 mL per min). AUC and half-life of febuxostat increased in subjects with renal impairment in comparison to subjects with normal renal function, but values were similar among three renal impairment groups. Mean febuxostat AUC values were up to 1.8 times higher in subjects with renal impairment compared to those with normal renal function. Mean C and AUC values for 3 active metabolites increased up to 2- and 4-fold, respectively. However, the percent decrease in serum uric acid concentration for subjects with renal impairment was comparable to those with normal renal function (58% in normal renal function group and 55% in the severe renal function group).
No dose adjustment is necessary in patients with mild to moderate renal impairment [see Dosage and Administration (2) and Use in Specific Populations (8.6)]. The recommended starting dose of ULORIC is 40 mg once daily. For patients who do not achieve a sUA less than 6 mg per dL after 2 weeks with 40 mg, ULORIC 80 mg is recommended. There is insufficient data in patients with severe renal impairment; caution should be exercised in those patients [see Use in Specific Populations (8.6)].
ULORIC has not been studied in end stage renal impairment patients who are on dialysis.
Hepatic Impairment: Following multiple 80 mg doses of ULORIC in patients with mild (Child-Pugh Class A) or moderate (Child-Pugh Class B) hepatic impairment, an average of 20-30% increase was observed for both C and AUC (total and unbound) in hepatic impairment groups compared to subjects with normal hepatic function. In addition, the percent decrease in serum uric acid concentration was comparable between different hepatic groups (62% in healthy group, 49% in mild hepatic impairment group, and 48% in moderate hepatic impairment group). No dose adjustment is necessary in patients with mild or moderate hepatic impairment. No studies have been conducted in subjects with severe hepatic impairment (Child-Pugh Class C); caution should be exercised in those patients [see Use in Specific Populations (8.7)].
Gender: Following multiple oral doses of ULORIC, the C and AUC of febuxostat were 30% and 14% higher in females than in males, respectively. However, weight-corrected C and AUC were similar between the genders. In addition, the percent decrease in serum uric acid concentrations was similar between genders. No dose adjustment is necessary based on gender.
Race: No specific pharmacokinetic study was conducted to investigate the effects of race.
Drug-Drug Interactions
Effect of ULORIC on Other Drugs
Xanthine Oxidase Substrate Drugs-Azathioprine, Mercaptopurine, and Theophylline: Febuxostat is an XO inhibitor. Drug interaction studies of ULORIC with drugs that are metabolized by XO (e.g., theophylline, mercaptopurine, azathioprine) have not been conducted. Inhibition of XO by ULORIC may cause increased plasma concentrations of these drugs leading to toxicity. ULORIC is contraindicated in patients being treated with azathioprine, mercaptopurine, and theophylline [see Contraindications (4) and Drug Interactions (7)].
Azathioprine and mercaptopurine undergo metabolism via three major metabolic pathways, one of which is mediated by XO. Although ULORIC drug interaction studies with azathioprine and mercaptopurine have not been c
