Probenecid (PBN)

Probenecid is a uricosuric drug that increases uric acid excretion in the urine. It is primarily used in treating gout and hyperuricemia. Probenecid was developed as an alternative to caronamide to competitively inhibit renal excretion of some drugs, thereby increasing their plasma concentration and prolonging their effects. In the kidneys, probenecid is filtered at the glomerulus, secreted in the proximal tubule and reabsorbed in the distal tubule. Probenecid works by interfering with the kidneys' organic anion transporter (OAT), which reclaims uric acid from the urine and returns it to the plasma. If probenecid (an organic acid) is present, the OAT binds preferentially to it (instead of to uric acid), preventing reabsorption of the uric acid. Hence, the urine retains more uric acid, lowering uric acid concentration in the plasma.