Pharmacokinetic and clinical studies of a new uricosuric agent - benzbromarone.

Benzbromarone, a potent uricosuric agent, is a benzofuran derivative with a bromine on the 3rd and 5th positions of the benzene ring. Readily absorbed after oral administration, it is promptly dehalogenated in the liver and excreted via the biliary system. Peak drug concentration usually precedes maximal uricosuria following a single dose of 40 mg of benzbromarone, since benzarone, one of the two metabolites, likewise has a uricosuric action. Longterm studies in 24 gouty patients indicate that the drug is well tolerated. It has not produced any skin rash or renal colic. Renal hemodynamics, blood picture, and liver enzymes were unchanged. Since it is eliminated by the biliary tract, it may cause diarrhoea in some patients. Being a very potent uricosuric agent, it is not advocated in patients with a history of uric acid lithiasis. The uricosuric effect is not liable to be counteracted when used in conjunction with hyperuricemic diuretics. The drug is particularly useful in patients with chronic gouty arthritis and tophi, either refractory or allergic to probenecid, sulfinpyrazone, or allopurinol.