By the Way, Doctor

An IV drug for osteoporosis?

(This article was first printed in the June, 2004 issue of the Harvard Women’s Health Watch. For more information or to order, please go to http://health.harvard.edu/women.)

Q My wife is 80. In order to increase her bone calcium, she takes calcium citrate tablets. Her doctor now wants to put her on Aredia by IV injection every three months. Since this is not FDA approved, is it a good idea?

A Good question. The FDA has approved pamidronate (Aredia) — and zolendronate (Zomesta), another drug in the same class — for cancer patients, not for osteoporosis. My recommendation would be for your wife to try alendronate (Fosamax) or risedronate (Actonel) first. All four of these medications are in the bisphosphonate (pronounced bis-FOS-fo-nate) class of drugs. But Fosamax and Actonel are approved for osteoporosis, and they’ve been shown to increase bone mass and reduce the risk for hip and vertebral fractures.

Your bones are continually being remodeled (some homeowners may identify!), which is the body’s way of keeping them strong. Cells in the bone called osteoclasts break down bone tissue, while others called osteoblasts build it up. The bisphosphonates work by reining in the osteoclasts; they may also prod the osteoblasts into working a bit harder.

Aredia and Zomesta are used to treat a common and serious problem for cancer patients — too much calcium in the blood (hypercalcemia). Some data suggest that they’re also effective in reducing pain and fracture risk when a cancer that originated elsewhere has metastasized to bones.

As long as a drug has been approved, doctors are permitted to prescribe it “off-label” for conditions other than the one for which it received FDA approval. Some doctors may be prescribing Aredia for osteoporosis because it can be given as an intravenous injection just once every three months. Zomesta, which also is an IV drug, may be given just once a year. The problem is that there are no data yet showing that either drug prevents fractures. And the main reason for treating osteoporosis is to prevent fractures, especially broken hips.

Fosamax and Actonel are once-a-week oral medications. They need to be taken on an empty stomach with an 8-ounce glass of water. You shouldn’t lie down, or eat or drink anything for 30 minutes afterward. One side effect is an inflamed and irritated esophagus (esophagitis), but that doesn’t happen very often.

If a patient of mine was bothered by esophagitis, I’d recommend trying either calcitonin (Calcimar or Miacalcin) or raloxifene (Evista) before trying Aredia. The chief drawback of calcitonin or raloxifene is that they have been shown to reduce vertebral, not hip, fractures.

— Soheyla Gharib, M.D.
Harvard Health Letter Editorial Board