Kidney Stones - Medications

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

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Cholestyramine. Cholestyramine (Questran, Questran Light) is a drug normally used to reduce cholesterol levels; it also binds with oxalate in the intestine and so reduces elevated 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, so many people cannot tolerate it. 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 four to six 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, and vitamin supplements may be necessary.

Investigative Therapies. The following are some investigative therapies for eliminating the causes of some kidney stones.

A deficiency in the intestinal bacteria Oxalobacter formigene is proving to be an important factor in some cases of calcium oxalate stones. Researchers are studying the use of enzymes contained in the bacteria or recolonizing the intestine with the bacterium itself as a preventive measure.
Some investigators are testing the elimination of nanobacteria, tiny infectious agents that might be important in the formation of many kidney stones. A 2002 laboratory study suggested that nanobacteria may be eliminated or reduced with tetracycline, bisphosphonates (drugs used in osteoporosis), potassium citrate, or 5-fluorouracil (an anti-cancer agent). This approach to treatment of human kidney stones is still experimental.

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 this 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.