Bisphosphonates: or “Patching up Faulty Construction” – By William P. Rix, M.D.

Posted on December 1, 2010 by NHOC Tech under Featured Articles

Last month we talked about osteoporosis and its risk for fragility fractures.   In addition to calcium, Vitamin D, and exercise, a class of drugs called bisphosphonates is often used to treat this common condition.

Bisphosphonates are anti-resorptive drugs that inhibit osteoclasts, the cells that break down bone and release calcium.   By slowing osteoclastic activity, osteoblasts, the bone building cells, gain advantage. The result is a stronger skeleton.

With 1.5 million fragility fractures occurring yearly in the US, there is much need for this class of drugs.   To put this in perspective, there is a 1 in 3 chance that a woman over 50 will sustain a fragility fracture at some point in her life.   Therefore, it is disappointing that, with 44 million people in the US being potential candidates for bisphosphonate treatment, relative few actually take this important drug.   This is especially disconcerting considering that when taken properly, bisphosphonates reduce the risk of sustaining fragility fractures by 50%.

Another problem is compliance: 50% of patients who are prescribed bisphosphonates stop taking the drug on their own after 6 – 12 months.   There are many theories to explain this behavior, but one factor may be fear of side effects.

As with many medications, side effects come with the territory.   Fortunately, with bisphosphonates,  the side effects of heartburn, muscular aches , and blurry vision, though common, are usually temporary.   Rare but more serious complications include osteonecrosis (bone death) of the jaw, esophageal cancer, and, paradoxically, atypical fractures of the femur.  These complications are so uncommon that it is difficult to actually prove a causal relationship with bisphosphonate therapy.  Nevertheless, because of a loose association, it is recommended that the patient stop taking the drug after 4-5 yrs of continuous use, thereby reducing the risk of these serious side effects.  The good news is that residual bisphosphonate remains in the body for years, continuing to do its good work protecting the skeleton.  There are other things you can do to help protect yourself from these rare but serious complications: maintain good dental hygiene; be aware of any vague persisting thigh pain; don`t put up with persistent heartburn.

Despite all this gloomy talk of side effects, the take home message is clear.   For a person who needs bisphosphonate therapy, the benefits of taking this important medication far outweigh the risks of not taking  it.