Are there OTC medications to treat uric acid kidney stones?

Sodium Bicarbonate (chewable tablets or powder) is probably the only readily available over-the-counter (OTC) medication to treat uric acid kidney stones. It is useful in patients who have persistent acidic urine as the cause of their uric acid stones. Patients 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 will make the urine too alkaline and promote the formation of calcium phosphate stones. 

Note: Consult your health care provider before starting any OTC or other medication. Patients taking sodium bicarbonate may experience an increase in side effects or a decrease in effectiveness of their current medications.