– Strontium ranelate (S12911), a strontium (II) salt of the ranelic acid, is a medication for osteoporosis. Studies indicate it can also slow the course of osteoarthritis of the knee. The drug is unusual in that it both increases deposition of new bone by osteoblasts and reduces the resorption of bone by osteoclasts. It is therefore promoted as a “dual action bone agent” (DABA) indicated for use in the treatment of severe osteoporosis.