The following adverse reactions have been identified during postapproval use of febuxostat tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Blood and Lymphatic System Disorders: agranulocytosis, eosinophilia.
Hepatobiliary Disorders: hepatic failure (some fatal), jaundice, serious cases of abnormal liver function test results, liver disorder.
Immune System Disorders: anaphylaxis, anaphylactic reaction.
Musculoskeletal and Connective Tissue Disorders: rhabdomyolysis.
Psychiatric Disorders: psychotic behavior including aggressive thoughts.
Renal and Urinary Disorders: tubulointerstitial nephritis.
Skin and Subcutaneous Tissue Disorders: generalized rash, Stevens-Johnson Syndrome, hypersensitivity skin reactions, erythema multiforme, drug reaction with eosinophilia and systemic symptoms, toxic epidermal necrolysis.
Febuxostat tablets are 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.
Drug interaction studies of febuxostat tablets with other drugs that are metabolized by XO (e.g., mercaptopurine and azathioprine) have not been conducted. Inhibition of XO by febuxostat tablets may cause increased plasma concentrations of these drugs leading to toxicity [see Clinical Pharmacology (12.3)]. Febuxostat tablets are contraindicated in patients being treated with azathioprine or mercaptopurine [see Contraindications (4)].
Drug interaction studies of febuxostat tablets with cytotoxic chemotherapy have not been conducted. No data are available regarding the safety of febuxostat tablets during cytotoxic chemotherapy.
Based on drug interaction studies in healthy patients, febuxostat tablets does not have clinically significant interactions with colchicine, naproxen, indomethacin, hydrochlorothiazide, warfarin or desipramine [see Clinical Pharmacology (12.3)]. Therefore, febuxostat tablets may be used concomitantly with these medications.
Limited available data with febuxostat tablets use in pregnant women are insufficient to inform a drug associated risk of adverse developmental outcomes. No adverse developmental effects were observed in embryo-fetal development studies with oral administration of febuxostat to pregnant rats and rabbits during organogenesis at doses that produced maternal exposures up to 40 and 51 times, respectively, the exposure at the maximum recommended human dose (MRHD). No adverse developmental effects were observed in a pre- and postnatal development study with administration of febuxostat to pregnant rats from organogenesis through lactation at an exposure approximately 11 times the MRHD (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
In an embryo-fetal development study in pregnant rats dosed during the period of organogenesis from gestation Days 7 – 17, febuxostat was not teratogenic and did not affect fetal development or survival at exposures up to approximately 40 times the MRHD (on an AUC basis at maternal oral doses up to 48 mg/kg/day). In an embryo-fetal development study in pregnant rabbits dosed during the period of organogenesis from gestation Days 6 – 18, febuxostat was not teratogenic and did not affect fetal development at exposures up to approximately 51 times the MRHD (on an AUC basis at maternal oral doses up to 48 mg/kg/day).
In a pre- and postnatal development study in pregnant female rats dosed orally from gestation Day 7 through lactation Day 20, febuxostat had no effects on delivery or growth and development of offspring at a dose approximately 11 times the MRHD (on an AUC basis at a maternal oral dose of 12 mg/kg/day). However, increased neonatal mortality and a reduction in neonatal body weight gain were observed in the presence of maternal toxicity at a dose approximately 40 times the MRHD (on an AUC basis at a maternal oral dose of 48 mg/kg/day).
Febuxostat crossed the placental barrier following oral administration to pregnant rats and was detected in fetal tissues.
There are no data on the presence of febuxostat in human milk, the effects on the breastfed infant, or the effects on milk production. Febuxostat is present in rat milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for febuxostat tablets and any potential adverse effects on the breastfed child from febuxostat tablets or from the underlying maternal condition.
Orally administered febuxostat was detected in the milk of lactating rats at up to approximately 7 times the plasma concentration.
Safety and effectiveness of febuxostat tablets in pediatric patients have not been established.
No dose adjustment is necessary in elderly patients. Of the total number of patients in Studies 1, 2 and 3 (clinical studies of febuxostat tablets in the treatment of gout) [see Clinical Studies (14.1)] , 16% were 65 and over, while 4% were 75 and over. Comparing patients in different age groups, no clinically significant differences in safety or effectiveness were observed but greater sensitivity of some older individuals cannot be ruled out. The Cmax and AUC24 of febuxostat following multiple oral doses of febuxostat tablets in geriatric patients (≥65 years) were similar to those in younger patients (18 to 40 years) [see Clinical Pharmacology (12.3)].
No dose adjustment is necessary in patients with mild or moderate renal impairment (Clcr 30 to 89 mL/min). For patients with severe renal impairment (Clcr 15 to 29 mL/min), the recommended dosage of febuxostat tablets is limited to 40 mg once daily [see Dosage and Administration (2.2) and Clinical Pharmacology (12.3)].
No dose adjustment is necessary in patients with mild or moderate hepatic impairment (Child-Pugh Class A or B). No studies have been conducted in patients with severe hepatic impairment (Child-Pugh Class C); therefore, caution should be exercised in these patients [see Clinical Pharmacology (12.3)].
No studies have been conducted in patients with secondary hyperuricemia (including organ transplant recipients); febuxostat tablets are not recommended for use in patients whom the rate of urate formation is greatly increased (e.g., malignant disease and its treatment, Lesch-Nyhan syndrome). The concentration of xanthine in urine could, in rare cases, rise sufficiently to allow deposition in the urinary tract.
Febuxostat tablets were studied in healthy subjects in doses up to 300 mg daily for seven days without evidence of dose-limiting toxicities. No overdose of febuxostat tablets were reported in clinical studies. Patients should be managed by symptomatic and supportive care should there be an overdose.
Febuxostat tablets are xanthine oxidase inhibitor. The active ingredient in febuxostat tablets are 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-1,3-thiazole-5-carboxylic acid hemihydrate, with a molecular weight of 325.38. The empirical formula is C16 H16 N2 O3 S. ½ H2 O
The chemical structure is:
Febuxostat hemihydrate is a non-hygroscopic, white to off white crystalline powder that is freely soluble in dimethylformamide; soluble in tetrahydrofuran; sparingly soluble in acetone and ethanol. The melting range is 203°C to 208°C.
Febuxostat tablets for oral use contain the active ingredient, febuxostat hemihydrate, and are available in two dosage strengths; 40 mg and 80 mg. Inactive ingredients include lactose monohydrate, microcrystalline cellulose, croscarmellose sodium, hydroxypropyl cellulose, colloidal silicon dioxide and magnesium stearate. Febuxostat tablets are coated with Opadry II, green. The components of Opadry II, green are D&C yellow #10 aluminium lake, FD&C blue #1/ Brilliant blue FCF aluminum lake, FD&C blue #2/ Indigo Carmine AL, Macrogol/PEG, polyvinyl alcohol-part hydrolyzed, talc, titanium dioxide.
All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.