Benzbromarone

How it works

It inhibits the URAT1 transporter in the proximal renal tubule, reducing reabsorption of uric acid and thereby increasing its urinary excretion.

Prescribing in practice

• It has been associated with rare but serious hepatotoxicity, so liver function must be monitored and the drug is reserved for selected patients under specialist guidance.
• It is not licensed in the UK and is used only on a named-patient or unlicensed basis where appropriate.
• Increasing urinary urate can precipitate urate stones; adequate fluid intake and urine alkalinisation may be advised, and it is less effective in significant renal impairment.

Monitoring

Monitor liver function periodically, particularly in the early months of treatment, alongside serum urate and renal function.

Counselling the patient

• Maintain a good fluid intake throughout treatment.
• Report yellowing of the skin or eyes, dark urine or persistent nausea, which may indicate liver problems.
• An acute flare of gout may occur when starting; do not stop treatment without advice.

Evidence & guidelines

Its uricosuric efficacy is well described in the gout literature, though use is limited by hepatotoxicity concerns and lack of UK licensing.