Doctor's Answers (1)
Medications to treat kidneys stones are used for 2 purposes
Dissolution of stones
Kidneys stones are made of various mineral compositions. 5-10% of kidneys stones are composed of uric acid. Only uric acid stones can be dissolved with medications. All other types of kidney stones such as calcium oxalate stones (the most common variety) cannot be dissolved with medication, and require other types of treatment.
Uric acid stones can be dissolved by alkalinising the urine, bring the pH of the urine to above 6.5.
Medications that can alkalinise urine include Potassium citrate and Sodium bicarbonate. If the patient also has gout or high uric acid in his blood, Allopurinol is a medication that can lower the uric acid level in the blood. It is also important to institute dietary changes to reduce purine rich foods such as alcohol and organ meats.
Prevention of recurrence of stones
After experiencing a painful stone, there is up to 50% chance of having another stone event within the next 5 years.
Blood and urine tests and analysis of stones that have been passed, can be done to look abnormalities that can contribute to stone recurrences, and dietary changes and medications to treat these abnormalities are tailored for the individual patient.
Citrate attaches to calcium in the urine preventing the formation of mineral crystals that form stones. For stone formers found to be low in citrate, increasing intake of citrus fruits or taking regular potassium citrate can correct this deficiency, and reduce the chance of stone recurrence. This is also helpful to prevent calcium oxalate and uric stones.
For people with high calcium levels in the urine or calcium phosphate stones, thiazide diuretics lower urinary calcium, and urine pH, to help reduce recurrence of calcium oxalate and calcium phosphate stones.
In summary, the prevention of stones is individualised to the patient and requires finding out the metabolic abnormalities that predispose a person to stone formation. Thereafter dietary changes should be made to overcome these abnormalities. This may sometimes be accompanied by taking medications directed at these abnormalities if dietary changes alone are not enough to correct the metabolic abnormalities.