Urinary alkalization for the treatment of uric acid nephrolithiasis

Three major conditions control the potential for uric acid stones: the quantitative excretion of uric acid, the volume of urine as it affects the urinary concentration of uric acid and the urinary pH. However, the most important factor for uric acid stone formation is acid urinary pH that is a prerequisite for uric acidic stone formation. Indeed the goal standard of urinary alkalization is to achieve a pH of 6-6.5. Administration of alkali should be titrated appropriately by pH paper to record urinary pH until a steady state is achieved. Alkali therapy such as sodium bicarbonate and potassium citrate has been advocated on the basis of established clinical experience, although potassium citrate should be preferred because it may avoid the complication of calcium salt precipitation. Recently it has been reported the clinical efficacy of therapy with potassium citrate/potassium bicarbonate for dissolution of radiolucent stones respect to control study period (only water daily intake of 1500 ml). Furthermore, mean urinary pH was significantly continuously higher during the alkali treatment study in comparison to the control study period, even though the mean of urinary volumes were similar in the two periods. In conclusion urinary alkalization with maintaining continuously high urinary pH values, could be the treatment of choice for stone dissolution and prevention of uric acid stones.