Kidney Stones - Treatment

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Phosphate compounds:

• Neutral (nonacidic) sodium or potassium phosphate (K-Phos, Neutral, Neutra-Phos) is usually taken four times a day after meals to prevent kidney stones unless otherwise directed by the doctor. Diarrhea is a possible side effect.
• Cellulose phosphate (Calcibind) is recommended only for severe hypercalciuria caused by excessive absorption of calcium from the intestines that is associated with recurrent calcium stones. However, this drug may increase oxalate levels and decrease magnesium levels, which can lead to stones. Restricting dietary oxalates, calcium, and ascorbic acid, and taking magnesium supplements may help offset these risks. Cellulose phosphate may also cause bloating.

Acidic forms of phosphate should not be used, since they increase the risks for both hypocitraturia and hypercalciuria.

Cholestyramine. Cholestyramine (Questran, Questran Light) is a drug used to reduce cholesterol levels. However, it also binds with oxalate in the intestine, so it is used to reduce elevated oxalate levels in urine (hyperoxaluria). The drug is usually taken in powder form, dissolved in water, milk, or fruit juice; it is also available as a chewable bar (Cholybar). Bloating and constipation are common side effects of this drug. The drug also interferes with other medications, including digoxin (Lanoxin) and warfarin, and may contribute to calcium loss and osteoporosis. In order to prevent such interactions, other drugs should be taken one hour before or 4 to 6 hours after taking cholestyramine. If the drug is taken for a long period of time, deficiencies of vitamins A, D, E, and K can result. Vitamin supplementation may be necessary.

Medications for Uric Acid Stones

Sodium Bicarbonate. Patients whose uric acid stones are caused by persistently acidic urine may take sodium bicarbonate to reduce acidity. Patients taking sodium bicarbonate must test their urine regularly with pH paper, which turns different colors depending on whether the urine is acidic or alkaline. Too much sodium bicarbonate can cause the urine to become overly alkaline and increase the risk for calcium phosphate stones. This treatment should not be used by patients who need to restrict sodium for other medical conditions.

Potassium Citrate. Potassium citrate, which restores citrate to the urine, is useful for patients with high levels of uric acid in the urine.