Febuxostat is a xanthine oxidoreductase inhibitor that has been developed to treat chronic gout. In healthy subjects, the pharmacokinetic parameters of febuxostat after multiple oral dose administration include an oral availability of about 85 %, an apparent oral clearance (CL/F) of 10.5 ± 3.4 L/h and an apparent volume of distribution at steady state (V /F) of 48 ± 23 L. The time course of plasma concentrations follows a two-compartment model. The initial half-life (t) is approximately 2 h and the terminal t determined at daily doses of 40 mg or more is 9.4 ± 4.9 h. Febuxostat is administered once daily. The maximum (peak) plasma concentrations are approximately 100-fold greater than the trough concentrations. Consequently, there is no significant accumulation of the drug during multiple dose administration. There are few data on the pharmacokinetics of febuxostat in patients with gout. While the pharmacokinetic parameters are not affected by mild to moderate hepatic impairment, there is no consensus on whether renal impairment has any effect on the pharmacokinetics of febuxostat. Febuxostat is extensively metabolised by oxidation (approximately 35 %) and acyl glucuronidation (up to 40 %); febuxostat acyl glucuronides are cleared by the kidney. In healthy subjects treated with multiple doses of febuxostat 10-240 mg, the concentrations of serum urate are reduced by a maximum of about 80 %. The percentage reduction in the concentrations of serum urate is slightly less in gouty patients than in healthy subjects.

BACKGROUND Internationally, most atrial fibrillation (AF) management guidelines recommend opportunistic screening for AF in people ≥65 years of age and oral anticoagulant treatment for those at high stroke risk (CHA₂DS₂‐VA≥2). However, gaps remain in screening and treatment. METHODS AND RESULTS General practitioners/nurses at practices in rural Australia (n=8) screened eligible patients (≥65 years of age without AF) using a smartphone ECG during practice visits. eHealth tools included electronic prompts, guideline‐based electronic decision support, and regular data reports. Clinical audit tools extracted de‐identified data. Results were compared with an earlier study in metropolitan practices (n=8) and nonrandomized control practices (n=69). Cost‐effectiveness analysis compared population‐based screening with no screening and included screening, treatment, and hospitalization costs for stroke and serious bleeding events. Patients (n=3103, 34%) were screened (mean age, 75.1±6.8 years; 47% men) and 36 (1.2%) new AF cases were confirmed (mean age, 77.0 years; 64% men; mean CHA₂DS₂‐VA, 3.2). Oral anticoagulant treatment rates for patients with CHA₂DS₂‐VA≥2 were 82% (screen detected) versus 74% (preexisting AF)( P =NS), similar to metropolitan and nonrandomized control practices. The incremental cost‐effectiveness ratio for population‐based screening was AU$16 578 per quality‐adjusted life year gained and AU$84 383 per stroke prevented compared with no screening. National implementation would prevent 147 strokes per year. Increasing the proportion screened to 75% would prevent 177 additional strokes per year. CONCLUSIONS An AF screening program in rural practices, supported by eHealth tools, screened 34% of eligible patients and was cost‐effective. Oral anticoagulant treatment rates were relatively high at baseline, trending upward during the study. Increasing the proportion screened would prevent many more strokes with minimal incremental cost‐effectiveness ratio change. eHealth tools, including data reports, may be a valuable addition to future programs. REGISTRATION URL: https://www.anzctr.org.au . Unique identifier: ACTRN12618000004268.

Xanthine oxidoreductase (XOR) is the rate-limiting enzyme in purine catabolism and converts hypoxanthine to xanthine, and xanthine into uric acid. When concentrations of uric acid exceed its biochemical saturation point, crystals of uric acid, in the form of monosodium urate, emerge and can predispose an individual to gout, the commonest form of inflammatory arthritis in men aged over 40 years. XOR inhibitors are primarily used in the treatment of gout, reducing the formation of uric acid and thereby, preventing the formation of monosodium urate crystals. Allopurinol is established as first-line therapy for gout; a newer alternative, febuxostat, is used in patients unable to tolerate allopurinol. This review provides an overview of gout, a detailed analysis of the structure and function of XOR, discussion on the pharmacokinetics and pharmacodynamics of XOR inhibitors-allopurinol and febuxostat, and the relevance of XOR in common comorbidities of gout.