Drugs known as bisphosphonates are huge sellers in the U.S., prescribed mostly for post-menopausal women to protect against bone fractures. The risk of osteoporosis (bone density loss) increases after menopause.

But the possible side effects of bisphosphonates have long been of concern if they’re taken for an extended period. Bisphosphonates have a long half-life, which means they can remain active in the body for years, and over time, users might experience cumulative damage.

In its column “Ask the Pharmacist,” Consumer Reports has renewed concern about bisphosphonates (Fosamax, Boniva, Actonel), and advises women with low bone density not severe enough to qualify as osteoporosis to forgo them. The benefits, CR says, do not appear to outweigh the risk sudden femur fractures and decay of the jaw bone.

We wrote about bone-building drugs a couple of years ago in the wake of lawsuits over the death of jaw bone tissue associated with the use of Fosamax, the most well-known bisphosphonate. Sometimes this adverse event requires surgery to remove parts of the jaw.

Another risk of this class of drugs is sudden femur (thigh bone) fractures that can happen during activity as simple as taking a step. Other unpleasant side effects include gastrointestinal ulcers, eye inflammation and incapacitating muscle, bone and joint pain.

Even the diagnosis of osteopenia—lowered bone mineral density that’s often a precursor to osteoporosis—does not warrant taking these drugs. CR supports its stance with recent analysis from the federal Agency for Healthcare Research and Quality (AHRQ).

In 2010, the FDA required Merck, the manufacturer of Fosamax, to issue new warnings about the risk of femur fractures. In June, as noted on AboutLawsuits.com, the FDA released new guidelines for taking bisphosphonates. They indicated that even people with osteoporosis should limit their exposure to bisphosphonates. The feds recommended, per an FDA report from 2011, that use be limited from three to five years, at least until more definitive data become available.

The 2011 report, according to AboutLawsuits, was issued before an FDA advisory committee was convened to review the risks associated with the long-term use of the medications. The panel favored stronger bone-fracture warning labels but did not finalize length-of-use recommendations.

Merck still faces hundreds of Fosamax fracture lawsuits.

To reduce your likelihood of brittle bones, according to Consumer Reports:

• Eat calcium-rich foods such as green leafy vegetables, low-fat dairy products, shellfish, canned sardines and salmon, and take supplements as directed by your doctor to ensure you're getting at least 1,200 milligrams of calcium per day.
• Check your vitamin D blood level. It should be greater than 30 nanograms per milliliter; supplement your diet as directed by your doctor.
• Spend 30 minutes or more each day doing weight-bearing exercises such as walking and weightlifting to support bones and increase muscle strength.
• Do a safety check of your home, which is where most falls occur.
• Learn tai chi or similar exercises to improve balance, and use a cane if necessary.
• Limit alcohol consumption and sleeping pills.