Benzbromarone

DescriptionBenzbromarone,a non-competitive inhibitor of xanthine oxidase，is apotent uricosuric drug used in the treatment of gout.Benzbromarone is a benzofuran derivative chemically related to amiodarone. It increases uric acid excretion by non-specificallyinhibiting its tubular reabsorption.lt is used in patients with venous disorders to prevent,retard,or reverse varicose degenerative changes in the vessel wall.Benzbromarone causes diarrhea (3-4% of patients), urate and oxalate stones,urinary sand,renal colic，and allergy in a small number of patients.Liver damage, which reverses after withdrawal, has been described (SEDA-18,108).

UsesBenzbromarone is a benzofuran derivative that has been reported to lower serum urate levels in animals and human studies. In normal and hyperuricaemic subjects, benzbromarone reduced serum uric acid levels by one-third to one-half. In comparison with other urate-lowering drugs, 80 mg of micronized or 100 mg of nonmicronized benzbromarone had equal urate-lowering activity to 1–1.5 g of probenecid or 400–800 mg of sulfinpyrazone. The mechanism of the urate-lowering activity of benzbromarone appears to be attributable to its uricosuric activity. In rats, benzobromarone inhibited urate reabsorption in the proximal tubules when given at 10 mg/kg i.v. In isolated rat liver preparation, benzbromarone inhibits xanthine oxidase in vitro but not in vivo . In humans, this compound only weakly inhibits xanthine oxidase and no increase in urinary excretion of xanthine or hypoxanthine was observed. After oral administration, about 50% of benzbromarone is absorbed. The drug undergoes extensive dehalogenation in the liver and is excreted mainly in the bile and feces. For control of gout the usual therapeutic dose is 100–200 mg daily. Benzbromarone has few side effects and is usually well tolerated.