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Uricosuric Agent — Potent URAT1 Inhibitor Pregnancy: Contraindicated — insufficient data; avoid

Benzbromarone

Brand names: Desuric (not UK licensed — available via MHRA named patient basis)

Adult dose

Dose: 50–100 mg once daily
Route: Oral
Frequency: Once daily with food
Max: 200 mg/day
Not licensed in UK — available via named patient or MHRA special import. Most potent uricosuric available. Used when allopurinol, febuxostat, and probenecid have failed or are contraindicated. Can be used in moderate renal impairment (unlike probenecid). Urine alkalinisation recommended to prevent uric acid stone formation.

Paediatric dose

Route:
Not routinely used in paediatric patients — seek specialist opinion

Dose adjustments

Renal

Can be used down to eGFR 20–30 mL/min — advantage over probenecid; reduce to 50 mg/day in moderate renal impairment

Hepatic

Contraindicated in hepatic impairment — severe hepatotoxicity (including fatal fulminant hepatic failure) reported

Clinical pearls

  • Withdrawn from German and UK markets in 2003 following fatal cases of hepatic failure — available only on named patient/compassionate use basis in UK; informed consent and hepatic monitoring mandatory
  • Most potent uricosuric agent available: benzbromarone can reduce serum urate by 50% (more than allopurinol or probenecid alone); valuable in refractory tophaceous gout
  • Can be used in moderate renal impairment (eGFR 20–30 mL/min) — unlike probenecid, which is ineffective below eGFR 30 mL/min; this is its key advantage
  • Warfarin interaction: benzbromarone is a potent CYP2C9 inhibitor — INR can double or treble; if unavoidable combination, weekly INR monitoring and significant dose reduction of warfarin required
  • BSR gout guidelines include benzbromarone as third-line option in tophaceous gout where allopurinol and febuxostat have failed — requires specialist referral and named patient prescription

Contraindications

  • Hepatic impairment — any degree
  • Uric acid urolithiasis
  • Acute gout attack
  • Pregnancy
  • Concurrent CYP2C9 inhibitors

Side effects

  • Hepatotoxicity — most serious adverse effect; fatal fulminant hepatic failure reported (rare); led to withdrawal in Germany and UK in 2003
  • Renal uric acid stone formation
  • GI disturbance
  • Diarrhoea
  • Initial gout flare precipitation

Interactions

  • Warfarin — potent CYP2C9 inhibitor; significantly increases warfarin levels; INR monitoring essential; avoid if possible
  • Aspirin — blocks uricosuric effect (same as probenecid)
  • Other hepatotoxic drugs — additive liver toxicity

Monitoring

  • LFTs monthly for first 6 months, then every 3 months — hepatotoxicity warning
  • Serum urate monthly
  • Renal function and urinalysis
  • INR if on warfarin
  • Signs of gout flare

Reference: BNFc; BNF 90; BSR Gout Guidelines 2017; NICE NG219; EULAR Gout Guidelines 2016; MHRA Named Patient Guidance. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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