Bone-forming agents in the management of osteoporosis

Abstract

Women often consult for the first time after osteoporosis has already become established. Medications have therefore been developed which can stimulate bone formation, with the ultimate goal of restoring bone quantity and quality and reducing spinal and peripheral fractures to a greater extent than can be obtained with inhibitors of bone resorption. Peptides of the parathyroid hormone family, when given intermittently, increase the number and activity of osteoblasts, leading to an increase in bone mass and in an improvement in skeletal architecture. Teriparatide (1-34 parathyroid hormone, PTH) reduces vertebral and non-vertebral fractures at a dose of 20 microg/day given in subcutaneous daily injections. 1-84 PTH reduces vertebral fractures, but results on non-vertebral fractures are lacking. Strontium ranelate, suggested to uncouple bone formation from bone resorption, reduces vertebral, non-vertebral and hip fractures in osteoporotic patients aged >74 years. Reduction of a vertebral fracture has also been shown in osteopenic patients. Long-term (5-year) data are available on vertebral, non-vertebral, major non-vertebral and hip fractures in osteoporotic patients. Combination/sequential treatments using inhibitors of bone resorption and bone-forming agents have been assessed in a variety of regimens. Benefits from the use of bone-forming agents appear to be largely independent of previous treatment with inhibitors of bone resorption. After treatment with an anabolic agent, the use of anti-resorptive medications maintains the benefit of the former treatment. Concomitant use of an inhibitor of bone resorption and a stimulator of bone formation has not, so far, showed any additional benefit compared with each medication given alone.