Xanthine Oxidase Inhibitor — Urate-lowering Therapy Pregnancy: Febuxostat should not be used during pregnancy (the potential risk for humans is unknown) and should not be used while breastfeeding (a risk to a suckling infant cannot be excluded) — UK SPC §4.6.

Febuxostat

Brand names: Adenuric

Used in: Gout

Febuxostat is a xanthine-oxidase inhibitor that lowers serum urate in the long-term management of gout, used as an alternative to allopurinol, particularly where allopurinol is not tolerated or is unsuitable.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Gout: 80 mg once daily. If serum uric acid is >6 mg/dL (357 micromol/L) after 2-4 weeks, 120 mg once daily may be considered

Route: Oral — may be taken with or without food

Frequency: Once daily

Max: The UK SPC does not state a maximum daily dose; the highest regimen described is 120 mg once daily

The therapeutic target is to decrease and maintain serum uric acid below 6 mg/dL (357 micromol/L); febuxostat works sufficiently quickly to allow retesting of serum uric acid after 2 weeks. Gout flare prophylaxis (with an NSAID or colchicine) for at least 6 months is recommended at treatment initiation. Treatment should not be started until an acute attack of gout has completely subsided; if a gout flare occurs during treatment, febuxostat should not be discontinued. Tumour lysis syndrome: recommended oral dose is 120 mg once daily, started two days before the beginning of cytotoxic therapy and continued for a minimum of 7 days; treatment may be prolonged up to 9 days according to chemotherapy duration as per clinical judgment. Elderly: no dose adjustment required. Hepatic impairment — gout: recommended dose in mild hepatic impairment is 80 mg; limited information in moderate impairment; efficacy and safety not studied in severe hepatic impairment (Child-Pugh class C). Paediatric: safety and efficacy in children under 18 years have not been established — no data are available. NOTE: US labelling differs from the UK SPC (US recommended starting dose 40 mg once daily, increased to 80 mg once daily if serum uric acid is not below 6 mg/dL after two weeks) — the doses above are the UK SPC values.

Dose adjustments

Renal

No dose adjustment is necessary in patients with mild or moderate renal impairment. Efficacy and safety have not been fully evaluated in patients with severe renal impairment (creatinine clearance <30 mL/min). US labelling limits the dose to 40 mg once daily in severe renal impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Recommended dosage is 40 mg or 80 mg once daily. The recommended starting dosage is 40 mg once daily. For patients who do not achieve a serum uric acid (sUA) less than 6 mg/dL after 2 weeks, the recommended dosage is 80 mg once daily. ( 2.1 ) Patients with severe renal impairment: Limit the dosage to 40 mg once daily. ( 2.2 , 8.6 ) Flare prophylaxis is recommended upon initiation of febuxostat tablets. ( 2.4 ) Can be administered without regard to food or antacid use. ( 2.1 ) 2.1 Recommended Dosage The recommended febuxostat tablets dosage is 40 mg or 80 mg once daily. The recommended starting dosage of febuxostat tablets is 40 mg once daily. For patients who do not achieve a serum uric …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-05-08. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to the active substance or to any of the excipients
US labelling additionally contraindicates febuxostat in patients being treated with azathioprine or mercaptopurine (not listed as a contraindication in the UK SPC §4.3) — verify locally

Side effects

Gout flares (common)
Liver function abnormalities
Diarrhoea and nausea (common)
Headache and dizziness (common)
Rash, pruritus, oedema and fatigue; dyspnoea (common)
Rare serious hypersensitivity reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS and acute anaphylactic reaction/shock; rare events of sudden cardiac death

Interactions

eMC §4.5 was not captured in this source bundle — the UK interaction list must be verified by the clinician
Azathioprine or mercaptopurine — concomitant administration with these xanthine oxidase substrate drugs could increase their plasma concentrations resulting in severe toxicity (US FDA label §7; contraindicated in US labelling)
Theophylline — febuxostat altered the metabolism of theophylline (a xanthine oxidase substrate) in humans; use with caution (US FDA label §7)
Cytotoxic chemotherapy — no drug interaction studies conducted; no data available on the safety of febuxostat during cytotoxic chemotherapy (US FDA label §7)
No clinically significant interactions with colchicine, naproxen or indomethacin in healthy-volunteer studies (US FDA label §7)

Clinical monograph

How it works

It inhibits xanthine oxidase, the enzyme that converts hypoxanthine and xanthine to uric acid, thereby reducing urate production and serum urate concentration.

Prescribing in practice

It must not be used with azathioprine or mercaptopurine, as inhibiting their metabolism causes dangerous accumulation and severe myelosuppression.
Starting treatment can precipitate acute gout flares, so co-prescribe flare prophylaxis when initiating and continue it for the recommended period.
Following an MHRA caution, avoid where possible in patients with significant pre-existing cardiovascular disease.

Monitoring

Monitor serum urate to confirm response, check liver function periodically as hepatic reactions can occur, and remain alert to cardiovascular symptoms in at-risk patients.

Counselling the patient

A gout flare may occur when starting; this does not mean the medicine is failing, and prophylaxis is given to reduce it.
Report a rash promptly, as serious skin reactions can rarely occur.
Do not take it with azathioprine or mercaptopurine; tell your prescriber if you are on either.

Evidence & guidelines

Recommended option for chronic hyperuricaemia in gout where allopurinol is unsuitable (NICE TA164; MHRA cardiovascular safety advice).

Reference: NICE NG219 (Gout); MHRA Febuxostat Safety Update 2019; FAST Trial (Lancet 2020); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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