Bone Loss Rx May Slow Bone Growth

Osteoporosis medication zoledronic acid may stop vital bone formation along with bone loss

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) After menopause, many women need treatment for bone loss due to osteoporosis. But a medication that prevents bone loss may also have the side effect of inhibiting bone growth.

A recent study tested the effects of an osteoporosis medication, zoledronic acid, on women’s bone loss and new bone formation biomarkers.

The results showed that while zoledronic acid may prevent bone loss, it also may get in the way of the process required for new bone formation—an important function in fighting osteoporosis.

"Get screened for osteoporosis after menopause."

Antonino Catalano, MD, PhD, from the Department of Internal Medicine at the University of Messina in Italy, led an investigation into the osteoporosis prescription, zoledronic acid.

Inside of bones are cells that must continue to generate replacement bone tissue to keep bones from becoming brittle. Old bone cells are absorbed back into the body as new ones form.

This cycle of reabsorption of old cells and generation of new cells is vital to maintaining proper bone structure. Osteoporosis is a condition of weak bone structure that can result in bone fractures from even very minor accidents.

Women who have gone through menopause are at the highest risk for osteoporosis.

There are several prescription medications on the market for the treatment of osteoporosis, including zoledronic acid (Zometa).

Sclerostin is a protein in the body involved in the regulation of old bone cell absorption. While zoledronic acid works to stop bone loss, the researchers in this study were concerned that it might also get in the way of sclerostin's vital role in bone reabsorption.  

For this small study, 40 postmenopausal women with osteoporosis were evenly split into two groups. The first group was assigned an injection of 5 mg of zoledronic acid and the second group was assigned a fake dose, or placebo, of non-medicated saline solution. Injections were given only once, which is the standard treatment.

The researchers took blood samples from each patient at 2, 7, 30 and 360 days after the injection to test for bone reabsorption, bone formation and sclerostin levels.

In the first group, sclerostin levels increased by day 2, peaked at day 7, decreased by day 30 and returned to nearly original levels by day 360.

Bone formation markers and bone reabsorption markers were reduced at every time point in the zoledronic acid group.

No bone marker changes were found in the placebo group.

The authors concluded that zoledronic acid increased sclerostin levels, and that sclerostin could play a role in blocking bone formation.

The authors recommended further studies continue to look into the use of zoledronic acid’s potentially harmful effects in osteoporosis patients.

The authors suggested that zoledronic acid might be used in combination with another therapy to reap the benefits of preventing bone loss and counteract the prevention new bone formation.

This study was published in April in the Journal of Clinical Endocrinology & Metabolism.

No outside funding sources were listed. No conflicts of interest were declared.

Reviewed by: 
Review Date: 
April 17, 2013
Last Updated:
December 18, 2013