Anabolic Drug Therapy in Osteoporosis

Summary

• Intermittent use of recombinant human parathyroid hormone (rhPTH) is the most promising anabolic treatment in osteoporosis, as it increases bone density and decreases the risk of vertebral and non-vertebral fractures in patients with severe osteoporosis (low bone density and prevalent vertebral fractures).

• The use of other anabolic agents such as growth hormone and IGF-I in the treatment of osteoporosis needs further study.

Osteoporosis is the result of a disequilibrium between bone formation and bone resorption. Currently, mainly anti-resorptive treatments are available for the treatment of osteoporosis and prevention of fractures (estrogens, SERMs, bisphosphonates, calcitonin). A new approach consists of the use of anabolic treatments, which stimulate bone turnover (both bone formation and bone resorption). We will discuss briefly some new insights about fluoride, anabolic steroids, growth hormone, and IGF-I. The use of rhPTH will be reviewed more extensively, as its anti-fracture effect has been well documented.

In most cases of osteoporosis, bone resorption is increased; anti-resorptive treatment has been shown to decrease the risk of fracture. Based on these results, it does not seem logical to use anabolic agents, which increase bone turnover. However, in several clinical situations, bone formation is decreased, such as in the elderly and in glucocorticoid-induced osteoporosis (GIOP). In several studies, it has been shown that stimulation of both bone formation and bone resorption with the induction of a positive bone balance can increase bone strength and decrease fracture risk.