XDH and gout: Febuxostat is a selective, non-purine, inhibitor of XO approved by the FDA in 2009, for management of patients with hyperuricemia in patients with gout but not for asymptomatic hyperuricemia2 Febuxostat is approved for use at doses of 40 and 80 mg/day in the USA; and up to 120 mg/day in Europe and 10–60 mg/day in Japan (18).