List of products in the National Drug Code with proprietary name . This medication is used to treat high blood calcium levels (hypercalcemia) that may occur with cancer. Zoledronic acid is also used with cancer chemotherapy to treat bone problems that may occur with multiple myeloma and other types of cancer (such as breast, lung) that have spread to the bones. Zoledronic acid belongs to a class of drugs known as bisphosphonates. It lowers high blood calcium levels by reducing the amount of calcium released from your bones into your blood. It also works by slowing the breakdown of your bones by cancer to prevent bone fractures.