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 of the kidney. Drugs that reduce blood uric acid are not all uricosurics; blood uric acid can be reduced by other mechanisms (see other ).
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.
The primary uricosuric drugs include probenecid, benzbromarone and sulfinpyrazone.
Drugs with other primary uses, that have known uricosuric properties, include losartan,atorvastatin, and fenofibrate. Although these drugs may have significant uricosuric action, their other significant pharmacological actions in off-label use as a uricosuric requires careful assessment of the patient to achieve the most benefit and least risk.