antilithic

from The Century Dictionary.

• In medicine, tending to prevent the formation of urinary calculus, or stone in the bladder.
• noun A medicine that tends to prevent the formation of urinary calculi.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Med.) Tending to prevent the formation of urinary calculi, or to destroy them when formed.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Acting against the formation of calculi, such as kidney stones.
• noun medicine A antilithic agent.