Fostat (Febuxostat) is an FDA approved non-purine, selective inhibitor of xanthine oxidase approve for the chronic management of hyperuricemia in patients with gout. It lowers serum uric acid levels by blocking xanthine oxidase; the enzyme responsible for uric acid production. Xanthine oxidase breaks down hypoxanthine to xanthine and then to uric acid. It inhibits the oxidized and reduced forms of xanthine oxidase but it has no significant effect on enzymes involved in purine and pyrimidine metabolism.

Fostat (Febuxostat) is indicated for the chronic management of hyperuricemia in patients with gout.

The recommended starting dose of Fostat (Febuxostat) is 40 mg once daily. For patients who do not achieve a serum uric acid less than 6 mg/dL after 2 weeks, Fostat (Febuxostat) 80 mg is recommended. Maximum recommended dose is 120 mg. No dose adjustment is necessary when it is prescribed for geriatric patients. Dose adjustment of Febuxostat is not necessary based upon gender. It is administered orally without regard to meal or antacid. Renal impairment: Dose adjustment is unnecessary in patients with mild to moderate renal impairment though in case of severe renal impairment (creatinine clearance <30 mol/min) data is insufficient. Hepatic impairment: Dose adjustment of is not necessary in patients with mild to moderate hepatic impairment.

Febuxostat is contraindicated in case of Ischaemic heart disease, CHF and in patients being treated with Azathioprine, Mercaptopurine or Theophylline.

An increase in gout flares is frequently observed during initiation of Febuxostat. If a gout flare occurs during treatment, Febuxostat need not be discontinued. Prophylactic therapy (i.e. NSAIDs or colchicine) may be beneficial for up to six months. Monitor for signs and symptoms of MI and

stroke and discuss with physician. Patient with severe renal or hepatic impairment should consult with physician before using Febuxostat. Transaminase elevations have been observed in Febuxostat treated patients. Monitor liver function tests periodically.

Safety and efficacy of Febuxostat in children below the age of 12 years have not been studied.

Pregnancy Category C. There is no adequate and well-controlled studies in pregnant women. Febuxostat should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Febuxostat is administered to a nursing mother.

Concomitant administration of Febuxostat with Azathioprine, Mercaptopurine or Theophylline could increase plasma concentrations of these drugs resulting severe toxicity.

The most common side effects of Febuxostat are liver problems, nausea, gout flares, joint pain and rash.

Febuxostat was studied in healthy subjects in doses up to 300 mg daily for seven days without evidence of toxicities.