POTASSIUM PHOSPHATE; SODIUM PHOSPHATE prevents kidney stones caused by too much calcium in the body. It works by making your urine more acidic, which prevents the build up of calcium. It may also be used to prevent and treat low phosphorus levels in your body. Phosphorus is a mineral that plays an important role in maintaining the health of your bones, muscles, digestive tract, and nervous system. This medication can also help antibiotics for UTIs work better.