Uricosuric

Uricosuric medications (drugs) are substances that increase the excretion of uric acid in the urine, thus reducing the concentration of uric acid in blood plasma. In general, this effect is achieved by action on the proximal tubule. Drugs that reduce blood uric acid are not all uricosurics; blood uric acid can be reduced by other mechanisms (see other Antigout medications).

Uricosurics are often used in the treatment of gout, a disease in which uric acid crystals form deposits in the joints. By decreasing plasma uric acid levels, uricosurics help dissolve these crystals, while limiting the formation of new ones. However, the increased uric acid levels in urine can contribute to kidney stones. Thus, use of these drugs is contraindicated in persons already with a high urine concentration of uric acid (hyperuricosuria). In borderline cases, enough water to produce 2 liters of urine per day may be sufficient to permit use of an uricosuric drug.

By their mechanism of action, some uricosurics (such as probenecid) increase the blood plasma concentration of certain other drugs and their metabolic products. While this is occasionally exploitable to good effect (see oseltamivir), assessment of drug interactions is very important when using uricosuric drugs in the presence of other medications.