<p>Febuxostat is a non-purine, selective xanthine oxidase (XO) inhibitor. It decreases serum uric acid level by inhibiting xanthine oxidase, which is responsible for uric acid production. Xanthine oxidase breaks down hypoxanthine to xanthine and thus to uric acid. Febuxostat is not expected to inhibit other enzymes involved in purine and pyrimidine synthesis and metabolism at therapeutic concentrations.</p>