Boning Up on Bone Drugs

Can a drug intended to prevent fractures cause them? The scoop on osteoporosis meds.

by Katharine Davis Fishman
Photograph: Photo: Coolife and Carole & Pauline

But there is an element of Russian roulette in the situation: Very few people get these odd femur fractures, and doctors can’t tell whether you’ll be one of them. So it’s important that people who take bisphosphonates be truly at risk for osteoporotic fractures. This calls into question the idea of using bisphosphonates as preventive medicine, and as a result the practice of routinely giving pills to almost every postmenopausal woman in her fifties with low bone density in order to ward off osteoporosis is becoming obsolete. However, some doctors probably haven’t gotten the memo yet. The reproductive endocrinologist—gynecologist Wulf Utian, the founder of the North American Menopause Society, points out that the U.S. is a large and diverse country, and prescribing practices are “all over the map.”

To better determine the benefit-risk ratio of taking bisphosphonates, the World Health Organization came up with FRAX, a test, still not widely used, that calculates your 10-year risk for osteoporotic fractures (see “What’s Your Bone-Break Risk?” on page 122). “In the early to mid 2000s, physicians relied almost exclusively on bone-density results and fracture history to make decisions about prescribing a bisphosphonate or other medication,” says Marjorie Luckey, medical director of the St. Barnabas Osteoporosis Center in Livingston, New Jersey. “Medication was often prescribed to prevent osteopenia from progressing to osteoporosis. But now we have tools that predict who’s at high risk for fractures so that we can target pharmacological treatment to those who need it most. The FRAX is not perfect, but it’s better than what we had before. With patients who have low bone density and are not at high risk for fractures in the near future, we try to convince them to take calcium and vitamin D, exercise regularly, stop smoking and limit alcohol. Many women can slow bone loss with just these steps once they are past the immediate menopause period.” (But if you’re taking bisphosphonates, you should continue unless your doctor advises you to stop, says the Endocrine Society.)

Some doctors now give patients, particularly those on Fosamax, a holiday of at least a year after a term of treatment. Here’s how that works, according to Lane: After you take Fosamax or a similar drug for three to five years, bone turnover, detected by a urine or blood test, begins to decrease, and the bone gets “sleepy”—that is, the collagen in the bone picks up chemicals that alter its properties, making it predisposed to fracture. When the bone markers in a blood or urine test go down, you stop the drug. Then you get the markers tested at regular intervals, and when they go up, you start using the drug again, perhaps at a smaller dose or in a weaker formulation.

How does all this research play out if you’re in your fifties and you’re told you have osteoporosis or a too-high fracture risk? A variety of effective drugs exist, and patients at high risk of fracture (like me) are now prescribed a nonbisphosphonate drug called For-teo, which offers the benefit of building new bone as well as preventing bone loss. Its sobering downsides, however, are that the patient must inject it into her stomach every day, it retails for $1,100-plus per month, and because of safety concerns, it can be taken for only two years maximum.

For other patients with osteoporosis, specialists may switch between medications. Lane may, for example, move a patient off the longest-lasting bisphosphonate, alendronate (Fosamax and its generic versions), to Actonel, a less powerful one. Another drug often used is the milder Evista, which is not a bisphosphonate. It has been shown to protect the spine, another potential site for osteoporotic fractures, but not the hip, and therefore only some patients will benefit from it. Evista has the added advantage of helping fend off breast cancer.

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