Treatment Options
Medication - Urocit-K

Urocit-K, on the other hand, is produced in a slow-release tablet form. These tablets are rather large and may be difficult for some patients to swallow if not broken prior to ingestion. The tablets are held together by a wax matrix, which often times will appear in a patient's bowel movement. This is a normal finding and should not be confused with intolerance to this product. The major advantage of Urocit-K over the liquid preparation is that its sustained release properties allow it to be taken on a twice a day basis. The typical starting dose of Urocit-K is 20 mEq twice a day.

For patients with calcium stone formation, urinary citrate levels should be maintained at or above 350 mg/L, while patients with uric acid stones should try to maintain a urinary pH of approximately 6.5.

Patients with uric acid stones should periodically monitor their urinary pH, as excessive levels of urinary alkalinization can increase the risk of calcium phosphate stone formation.

Uric Acid Stone Formation
Kidney stones composed of uric acid are commonly seen in patients suffering from recurrent stone disease. In fact, high levels of urinary uric acid increases the risk for both uric acid stones as well as calcium stones. This occurs because calcium oxalate crystals are attracted to uric acid crystals which can often lead to a mixed stone in which the core is composed of uric acid and the shell composed of calcium oxalate. Elevated urinary uric acid levels can be due to a variety of causes. While the majority of urinary uric acid is the results of normal body metabolism, significant amounts of uric acid can be due to a diet high in purine content.

Foods that have high purine levels include most meat, fish, and poultry products. Specifically, these foods include salmon, most fresh and salt water fish, shellfish, all forms of poultry including chicken, as well as the vast majority of pork and beef products, especially organ meats. Beans are a non-meat product that also have high levels of purines.

Patients at high risk for uric acid stones should avoid the consumption of organ meats and beans and should limit their total meat intake to approximately 4 ounces per day.

Other patients at risk for uric acid stone formation include those with certain forms of cancer, especially leukemia and lymphoma. Additionally, patients who are undergoing chemotherapy have very high levels of urinary uric acid and are at increased risk for kidney stone formation. This occurs in these patient groups because there is a significant increase in the amount of cellular breakdown products of which purines are an important component.

Approximately 25% of patients suffering from gout will eventually develop uric acid kidney stones. Additionally, approximately 25% of patients who have high urinary uric acid levels eventually develop gout.

If lowering a patient's total protein intake is not enough to prevent uric acid kidney stone formation, then alkalinizing agents such as Urocit-K can be especially helpful. Urocit-K, in addition to increasing urinary citrate levels, also causes the urine to become more alkaline (less acidic). Making the urine more alkaline can significantly decrease the chances of uric acid stone formation, as uric acid requires an acidic urine for crystallization.

The highly motivated patient who prefers periodic urinary dipstick evaluations should try to keep their urinary pH at approximately 6.5. It is not advisable to alkalinize the urine to higher levels, as this actually increases the risk of calcium phosphate stone production. The standard dose of Urocit-K used initially is 20mEq twice a day.