Diseases associated with low bone density result when the rate at which bone resorption is faster than the rate of bone formation. Bone resorption is a natural process within the body in which minerals are released from the breakdown of bone by cells called osteoclasts. Conversely, bone formation is the development of new bone tissue by cells called osteoblasts. Usually, the two processes are maintained in a delicate balance, but sometimes, bone is broken down faster than it is formed and the balance is disrupted causing diseases like osteoporosis, Paget’s disease, and fibrous dysplasia.
Luckily, doctors have a repertoire of tools to repair such a disrupted balance. One tool is parathyroid hormone (PTH), which enhances bone formation. Another tool is a certain class of drugs called biphosphonates. Biphosphonates inhibit the function of osteoclasts thus decreasing bone resorption. Of course, it is natural to think that the effects of both bisphosphonates and PTH together on low bone density diseases would be additive. This is to say that one would heal faster and more effectively if he/she underwent both treatments than if he/she were to undergo just one of the two treatments. However this is not the case!
In a study at the Hospital for Special Surgery, it was found that biphosphonates like alendonate (the active ingredient of Flomax) actually hinder the effects of PTH. How? PTH enhances bone formation by producing a signal that activates cells to build to new bone tissue. Biphosphonates, however, block the parathyroid hormone’s ability to produce this signal thus hindering the overall effects of PTH.
Issack PS, Laureman MH, Helfelt DL, Doty SB, Lane JM. Alendronate Inhibits PTH (1-34)-induced Bone Morphogenetic Protein Expression in MC3T3-E1 Preosteoblastic Cells. HSS J. 2007; 3(2): 169-72.
Eric R. Braverman, M.D.
Dr. Braverman is a Summa Cum Laude and Phi Beta Kappa graduate of Brandeis University and NYU Medical School, did brain research at Harvard Medical School, and trained at an affiliate of Yale Medical School. He is acknowledged worldwide as an expert in brain-based diagnosis and treatment, and he lectures to and trains doctors in anti-aging medicine.