Etidronate is used to treat Paget’s disease of bone (a condition in which the bones are soft and weak and may be deformed, painful, or easily broken) and to prevent and treat heterotopic ossification (growth of bone tissue in an area of the body other than the skeleton) in people who have had total hip replacement surgery (surgery to replace the hip joint with an artificial joint) or in people who have had an injury to the spinal cord. Etidronate is in a class of medications called bisphosphonates.