Febuxostat: uses, appearance and warnings

Febuxostat tablet is a xanthine oxidase (XO) inhibitor indicated for the chronic management of hyperuricemia in adult patients with gout who have an inadequate response to a maximally titrated dose of allopurinol, who are intolerant to allopurinol, or for whom treatment with allopurinol is not advisable. Febuxostat tablet is a xanthine oxidase (XO) inhibitor indicated for the chronic management of hyperuricemia in adult patients with gout who have an inadequate response to a maximally titrated dose of allopurinol, who are intolerant to allopurinol, or for whom treatment with allopurinol is not advisable. ( 1 ) Limitations of Use : Febuxostat tablets are not recommended for the treatment of asymptomatic hyperuricemia. ( 1 ) Limitations of Use : Febuxostat tablets are not recommended for the treatment of asymptomatic hyperuricemia.

40 mg tablets, white or almost white round film-coated tablets, debossed with "C33" on one side and blank on the other side. 80 mg tablets, white or almost white capsule-shaped film-coated tablets, debossed with "C32" on one side and blank on the other side. Tablet: 40 mg, 80 mg. ( 3 )

Febuxostat tablets 40 mg are white or almost white round film-coated tablets, debossed with “C33” on one side and blank on the other side and supplied as: NDC Number Size 72303-0855-1 Bottle of 30 Tablets Febuxostat tablets 80 mg are white or almost white capsule-shaped film-coated tablets, debossed with “C32” on one side and blank on the other side and supplied as: NDC Number Size 72303-0856-1 Bottle of 30 Tablets Protect from light. Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature].

Febuxostat tablets are contraindicated in patients being treated with azathioprine or mercaptopurine [see Drug Interactions (7) ] . Febuxostat tablets are contraindicated in patients being treated with azathioprine or mercaptopurine. ( 4 )

Gout Flares : An increase in gout flares is frequently observed after initiation of febuxostat tablets. If a gout flare occurs during treatment, febuxostat tablets need not be discontinued. Prophylactic therapy (i.e., non-steroidal anti-inflammatory drug or colchicine) upon initiation of treatment may be beneficial for up to six months. ( 2.4 , 5.2 ) Hepatic Effects : Cases of hepatic failure, some fatal, have been reported. If liver injury is detected, promptly interrupt febuxostat tablets and treat cause, if possible, to resolution or stabilization. Permanently discontinue febuxostat tablets if liver injury is confirmed, and no alternate etiology can be found. ( 5.3 ) Serious Skin Reactions : Serious skin and hypersensitivity reactions, including Stevens-Johnson Syndrome, drug reaction with eosinophilia and systemic symptoms and toxic epidermal necrolysis have been reported in patients taking febuxostat tablets. Discontinue febuxostat tablets if serious skin reactions are suspected. ( 5.4 ) 5.1 Cardiovascular Death In a cardiovascular (CV) outcome study, gout patients with established CV disease treated with febuxostat tablets had a higher rate of CV death compared to those treated with allopurinol. Sudden cardiac death was the most common cause of adjudicated CV deaths, 2.7% in the febuxostat tablets group (83 of 3,098) as compared to 1.8% in the allopurinol group (56 of 3,092). Febuxostat tablets were similar to allopurinol for nonfatal myocardial infarction (MI), nonfatal stroke and unstable angina with urgent coronary revascularization [see Clinical Studies (14.2) ] . Because of the increased risk of CV death, febuxostat tablets should only be used in patients who have an inadequate response to a maximally titrated dose of allopurinol, who are intolerant to allopurinol, or for whom treatment with allopurinol is not advisable [see Indications and Usage(1) ] . Consider the risks and benefits of febuxostat tablets when deciding to prescribe or continue patients on febuxostat tablets. Consider use of prophylactic low-dose aspirin therapy in patients with a history of CV disease. Monitor patients for the development of CV events. Inform patients about the symptoms of serious CV events and the steps to take if they occur. 5.2 Gout Flares After initiation of febuxostat tablets, an increase in gout flares is frequently observed. This increase is due to reduction in serum uric acid levels, resulting in mobilization of urate from tissue deposits. In order to prevent gout flares when febuxostat tablets are initiated, concurrent prophylactic treatment with an NSAID or colchicine is recommended [see Dosage and Administration (2.4) ]. 5.3 Hepatic Effects Cases of fatal and nonfatal hepatic failure in patients taking febuxostat tablets have been reported. During randomized controlled studies, transaminase elevations greater than three times the upper limit of normal (ULN) were observed (AST: 2%, 2%, and ALT: 3%, 2% in febuxostat tablets and allopurinol-treated patients, respectively). No dose-effect relationship for these transaminase elevations was noted [see Clinical Pharmacology (12.3) ] . Obtain a liver test panel (serum alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase, and total bilirubin) as a baseline before initiating febuxostat tablets. Measure liver tests promptly in patients who report symptoms that may indicate liver injury, including fatigue, anorexia, right upper abdominal discomfort, dark urine or jaundice. In this clinical context, if the patient presents abnormal liver tests (ALT or AST greater than three times the upper limit of the reference range), interrupt febuxostat tablets treatment while investigating the probable cause. Permanently discontinue febuxostat tablets if liver injury is confirmed, and no alternate etiology can be found. Permanently discontinue febuxostat tablets in patients who have serum ALT or AST greater than three times the reference range with serum total bilirubin greater than two times the reference range without alternative etiologies because they are at risk for severe drug-induced liver injury. For patients with lesser elevations of serum ALT or bilirubin and with an alternate probable cause, treatment with febuxostat tablets can be used with close monitoring. 5.4 Serious Skin Reactions Serious skin and hypersensitivity reactions, including Stevens-Johnson Syndrome, drug reaction with eosinophilia and systemic symptoms (DRESS) and toxic epidermal necrolysis (TEN) have been reported postmarketing in patients taking febuxostat tablets. Discontinue febuxostat tablets if serious skin reactions are suspected [see Patient Counseling Information (17) ]. Many of these patients had reported previous similar skin reactions to allopurinol. Febuxostat tablets should be used with close monitoring in these patients.

The following serious adverse reactions are described elsewhere in the prescribing information: Cardiovascular Death [see Warnings and Precautions (5.1) ] Hepatic Effects [see Warnings and Precautions (5.3) ] Serious Skin Reactions [see Warnings and Precautions (5.4) ] Adverse reactions in ≥ 1% of patients treated with febuxostat tablets are liver function abnormalities, nausea, arthralgia, and rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact HEC Pharm USA Inc. at 1-800-610-5709 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. …

Concomitant administration of febuxostat tablets with XO substrate drugs, azathioprine or mercaptopurine could increase plasma concentrations of these drugs resulting in severe toxicity. ( 7 ) 7.1 Xanthine Oxidase Substrate Drugs Febuxostat tablet is an XO inhibitor. Based on a drug interaction study in healthy patients, febuxostat altered the metabolism of theophylline (a substrate of XO) in humans [see Clinical Pharmacology (12.3) ]. Therefore, use with caution when coadministering febuxostat tablets with theophylline. A drug interaction study of febuxostat tablets and azathioprine, also metabolized by XO, showed an increase in exposure of 6-mercaptopurine which may lead to toxicity [see Clinical Pharmacology (12.3) ] . Drug interaction studies of febuxostat tablets with other drugs that are metabolized by XO (e.g., mercaptopurine) have not been conducted. …