Probenecid

Probenecid is a uricosuric and renal tubular blocking agent and is used in combination with colchicine to treat chronic gouty arthritis when complicated by frequent, recurrent acute attacks of gout. It inhibits the reabsorption of urate at the proximal convoluted tubule, thus increasing the urinary excretion of uric acid and decreasing serum urate levels. Effective uricosuria reduces the miscible urate pool, retards urate deposition, and promotes resorption of urate deposits. At the proximal and distal tubles, probenecid competitively inhibits the secretion of many weak organic acids including penicillins, most cephalosporins, and some other _-lactam antibiotics. This results in an increase in the plasma concentrations of acidic drugs eliminated principally by renal secretion, but only a slight increase if the drug is eliminated mainly by filtration. Thus, the drug can be used for therapeutic advantages to increase concentrations of certain _-lactam antibiotics in the treatment of gonorrhea, neurosyphilis, or pelvic inflammatory disease (PID).