Ibandronate (Boniva - Roche/GSK), a new oral bisphosphonate, was recently approved by the FDA in a once-monthly formulation for prevention and treatment of postmenopausal osteoporosis. The drug was initially approved in 2003 as a daily tablet, but was not marketed. An intravenous formulation for use once every 3 months is under investigation.

Risedronate (Actonel - Procter & Gamble), a pyridinyl bisphosphonate, has been approved by the FDA for oral treatment of Paget's disease of bone. Characterized by excessive bone resorption, bony deformity, disorganized bone remodeling and structural weakness, Paget's disease occurs in up to 3% of people older than 55 in Europe and North America (PD Delmas and PJ Meunier, N Engl J Med, 336:558, 1997).

A new enteric-coated delayed-release formulation of risedronate (Atelvia – Warner Chilcott) has been approved by the FDA for treatment of postmenopausal osteoporosis. Unlike immediate-release risedronate (Actonel) and all other oral bisphosphonates, which must be taken after an overnight fast and at least 30 minutes before eating breakfast, the new formulation is taken immediately after breakfast with at least 4 ounces of water. Then the patient must remain upright for at least 30 minutes.CLINICAL TRIAL — Approval of Atelvia was based on a 52-week non-inferiority study in more than 900...

The bisphosphonate risedronate (Actonel - Procter & Gamble) was recently approved by the FDA in a 150- mg once-monthly oral tablet for prevention and treatment of postmenopausal osteoporosis. The drug is also available for the same indication in 5-mg daily, 35-mg weekly and 75-mg twice-monthly tablets.

Tiludronate (Skelid - Sanofi), a chloro-4-phenylthiomethylene bisphosphonate, has been approved by the US Food and Drug Administration (FDA) for treatment of Paget's disease of bone. Characterized by excessive bone resorption and disorganized bone remodeling, Paget's disease occurs in up to 3% of people more than 55 years old in Europe and North America (PD Delmas and PJ Meunier, N Engl J Med, 336:558, Feb 20, 1997).

Raloxifene (Evista - Lilly), a benzothiophene that acts on estrogen receptors, has recently been marketed for prevention of postmenopausal osteoporosis. Only estrogen (alone or in combination with a progestin) and the bisphosphonate alendronate (Fosamax) were previously approved by the FDA for this indication.

View the Comparison Table: Some Drugs for Postmenopausal Osteoporosis

Zoledronic acid (Reclast - Novartis) is the first bisphosphonate approved by the FDA for once-yearly intravenous (IV) treatment of osteoporosis in postmenopausal women. Reclast is also approved for treatment of Paget's disease. Another IV formulation of zoledronic acid (Zometa) is approved for treatment of hypercalcemia of malignancy, multiple myeloma and bone metastases from solid tumors.

Use of alendronate (Fosamax), estrogen and other drugs for prevention and treatment of osteoporosis (Medical Letter, 38:1, 1996) has been accompanied by widespread availability of bone density screening tests, not only in doctors offices and hospitals, but even in retail stores. Bone densitometry provides a quantitative measurement of bone mineralization that can be used to predict the risk of osteoporotic fractures.

The FDA and two of its advisory committees have been debating whether to recommend limiting the duration of use of bisphosphonates in order to prevent atypical femoral fractures and possibly other side effects of the drugs. The agency produced a 182-page background document on this subject for a joint meeting of the Reproductive Health Drugs and the Drug Safety and Risk Management Advisory Committees held on September 9, 2011 (www.fda.gov). The document concluded that there is no clear evidence, with regard to fractures, of benefit or harm in continuing the drugs beyond 3-5 years. The two...