Pharmacologic treatment is recommended for postmenopausal women who have bone density T-scores (standard deviations from normal mean values in the spine, femoral neck, total hip, or distal radius) of -2.5 or below, T-scores between -1.0 and -2.5 with a history of fragility (low-trauma) fracture of the hip or spine, or T-scores between -1.0 and -2.5 with a FRAX 10-year probability of ≥3% for hip fracture or ≥20% for major osteoporotic fracture.

View the Comparison Table: Some Drugs for Postmenopausal Osteoporosis

US guidelines recommend pharmacologic therapy for postmenopausal women with a bone density T-score (standard deviation from normal mean values in healthy young women) of -2.5 or below in the lumbar spine, femoral neck, total hip, or distal radius, a T-score between -1.0 and -2.5 and a history of fragility (low-trauma) fracture of the hip or spine, or a T-score between -1.0 and -2.5 and a FRAX 10-year probability of ≥3% for hip fracture or ≥20% for major osteoporotic fracture (hip, clinical spine, humerus, distal radius).

View the Comparison Table: Some Drugs for Postmenopausal Osteoporosis

The FDA has approved romosozumab-aqqg (Evenity – Amgen), a sclerostin inhibitor, for once-monthly subcutaneous (SC) treatment of osteoporosis in postmenopausal women who are at high risk for fracture (history of osteoporotic fracture or multiple risk factors for fracture) or who have failed or cannot tolerate other drugs for this indication. Romosozumab is the first sclerostin inhibitor to be approved in the US and the third drug for treatment of postmenopausal osteoporosis that stimulates bone formation; the parathyroid hormone (PTH) receptor agonists abaloparatide (Tymlos) and teriparatide (Forteo) were approved earlier. Other drugs used for treatment of postmenopausal osteoporosis, such as bisphosphonates, inhibit bone resorption and decrease bone turnover.

Diagnosis of osteoporosis is based on the results of bone mineral density (BMD) testing or by the occurrence of a fragility fracture. Bone densitometry results are generally reported in terms of standard deviations (SD) from the mean value for young adults (T-score). The World Health Organization (WHO) defines osteoporosis in women as a T-score of -2.5 or below in the spine, femoral neck, or total hip. A computerized model (FRAX) is available that estimates the 10-year probability of a hip fracture or other major osteoporotic fracture based on clinical risk factors and BMD at the femoral neck.

View the Comparison Table: Drugs for Postmenopausal Osteoporosis

View the Comparison Table: Drugs for Postmenopausal Osteoporosis

US guidelines for the treatment of osteoporosis have been published. The diagnosis of osteoporosis has traditionally been established by the occurrence of fragility fractures or by bone densitometry, which is generally reported in terms of standard deviations (SD) from mean values in young adults (T-score). The World Health Organization (WHO) has defined normal bone mineral density (BMD) for women as a value within one SD of the young adult mean. Values 2.5 SD or more below the mean (T-score -2.5 or below) at the spine, femoral neck, or total hip are defined as osteoporosis. The WHO has developed a computerized model (FRAX) that predicts the 10-year probability of a hip fracture or other major osteoporotic fracture based on clinical risk factors and BMD at the femoral neck.

Long-term use of bisphosphonates for prevention and treatment of osteoporosis has been associated with osteonecrosis of the jaw, atypical fractures of the femur, and possibly esophageal cancer. So for how long should patients take them?

Disease-modifying anti-rheumatic drugs (DMARDs) are now used early in the treatment of rheumatoid arthritis (RA) to achieve clinical remission, prevent irreversible damage to joints, and minimize toxicity associated with nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids. DMARDs (Table 1) generally do not have an immediate analgesic effect, but over time can control symptoms and have been shown to delay and possibly stop progression of the disease. NSAIDs have immediate analgesic and antiinflammatory effects, but may not affect the disease process. Oral corticosteroids can relieve joint symptoms and control systemic manifestations, but their chronic use can cause many complications. Judicious use of intra-articular corticosteroids can rapidly decrease inflammation in acute joints with few, if any, adverse effects.

Osteoporosis is characterized by low bone mass with microarchitectural disruption and skeletal fragility that results in an increased risk of fracture. The diagnosis has traditionally been established by bone densitometry, which is generally reported in terms of standard deviations (SD) from mean values in young adults (T-score). The World Health Organization (WHO) has defined normal bone mineral density (BMD) for women as a value within one SD of the young adult mean. Values 2.5 SD or more below the mean (T score -2.5) are defined as osteoporosis. The WHO has developed a computerized model (FRAX) that predicts the 10-year probability of a hip fracture or any other major osteoporotic fracture based on clinical risk factors and BMD at the femoral neck.

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 advisory committees recommended that the labels for these drugs clarify their duration of use; they did not specify what that duration should be. A Treatment Guidelines from The Medical Letter issue on Drugs for Postmenopausal Osteoporosis will be published in November.

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The In-Brief article on delayed-release risedronate in issue 1360 (Med Lett Drugs Ther 2011; 53:24) included a statement that alendronate is currently the only bisphosphonate available generically. That would have been accurate if we had added "that is FDA-approved for treatment of osteoporosis." Etidronate (Didronel, and others), which was the first bisphosphonate used to treat osteoporosis (Medical Letter 1990; 32:111) but was never approved for such use by the FDA, is also available generically. It is approved for treatment of Paget's disease and for prevention and treatment of heterotropic ossification following hip replacement and in spinal-cord injured patients.

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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 postmenopausal women comparing the new 35-mg delayed-release tablet taken once each week to the original immediate-release 5-mg tablet taken daily at least 30 minutes before breakfast. (FDA approval of risedronate was based on studies with the 5-mg tablet taken once daily; now Actonel is usually taken, like Atelvia, as a 35-mg tablet once a week.) Increases in bone mineral density at the lumbar spine and other locations and changes in markers of bone turnover were similar in both groups. Diarrhea and abdominal pain occurred more frequently with the new formulation once weekly after breakfast than with risedronate 5 mg daily (8.8% vs. 4.9% and 5.2% vs. 2.9%, respectively).1

DOSAGE AND COST — Atelvia is available as a 35-mg tablet taken once each week. A month’s supply of the new formulation (four 35-mg tablets) costs $119.99, which is similar to the cost of Actonel once a week ($126.47).2 Alendronate (Fosamax, and others) is currently the only bisphosphonate available generically that is FDA-approved for treatment of osteoporosis; a month’s supply is available at some discount pharmacies for $9.

CONCLUSION — Taking the new enteric-coated delayed-release formulation of risedronate (Atelvia) after breakfast presumably would be more convenient than taking immediate-release risedronate 30 minutes before breakfast, but it may cause more diarrhea. Generic alendronate costs much less than either one.

1. MR McClung et al. BMD response to delayed-release risedronate 35 mg once-a-week formulation taken with or without breakfast. J Clin Densitom 2010; 13:132; Poster number 067.

2. Cost at drugstore.com. Accessed March 14, 2011.

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Disease-modifying anti-rheumatic drugs (DMARDs) are now used early in the treatment of rheumatoid arthritis (RA) to prevent irreversible damage to joints and minimize toxicities associated with nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids.

Osteoporosis is characterized by low bone mass with microarchitectural disruption and skeletal fragility that results in an increased risk of fracture. The diagnosis has traditionally been established by bone densitometry, which is generally reported in terms of standard deviations (SD) from mean values in young adults (T score). The World Health Organization (WHO) has defined normal bone mineral density (BMD) for women as a value within one SD of the young adult mean. Values 2.5 SD (T score -2.5) or more below the mean are defined as osteoporosis. The WHO has developed a computerized model (FRAX) that predicts the 10-year probability of hip fracture based on clinical risk factors and BMD at the femoral neck.

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.

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.

Many drugs are now marketed for treatment of postmenopausal osteoporosis, but questions remain about their use.

A 10-year study of daily oral alendronate (Fosamax) and a 7-year study of daily oral risedronate (Actonel) indicate that both drugs maintained increases in bone mineral density (BMD) and decreases in markers of bone remodeling throughout the study period. Both drugs are now more commonly taken once weekly. Available data are insufficient to compare fracture rates with alendronate and risedronate, and fracture rates are considered the most important endpoint in osteoporosis studies. Recent reports of severe pain and jaw osteonecrosis with these drugs are disturbing.

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.

The FDA has approved a new low-dose estrogen patch (Menostar - Berlex) for prevention of osteoporosis in postmenopausal women. Unlike other estrogen patches, it is not approved for treatment of hot flashes or other menopausal symptoms. Promotional material from the manufacturer suggests that this low dose of estrogen could prevent osteoporosis without some of the adverse effects of higher doses.

Teriparatide (ter i par' a tide; Forteo - Lilly), a recombinant segment of human parathyroid hormone, has been approved by the FDA for parenteral treatment of osteoporosis in post-menopausal women, and in men with idiopathic or hypogonadal osteoporosis, who are at high risk for fracture. Teriparatide is the first approved treatment for osteoporosis that stimulates bone formation. Other drugs approved for this indication inhibit bone resorption (Treatment Guidelines from the Medical Letter 2002;1:13).

Many drugs are now marketed for treatment of post-menopausal osteoporosis (PD Delmas, Lancet 2002; 359:2018). Prevention of this disorder has been complicated by the news that hormone replacement therapy (HRT), which many women have been taking to prevent osteoporosis, increases the incidence of coronary heart disease and that of breast cancer, stroke and pulmonary embolism as well (Medical Letter 2002; 44:78).

A once-weekly 35-mg oral formulation of the bisphosphonate risedronate (Actonel) has been approved by the FDA for prevention and treatment of postmenopausal osteoporosis. A once-weekly formulation of alendronate (Fosamax) was approved last year (Medical Letter 2001; 43:26). Bisphosphonates bind to the mineral surface of bone and decrease osteoclast activity, inhibiting the resorption phase of the bone turnover cycle. These drugs are not metabolized and remain bound to bone for several weeks.

Once-a-week formulations of alendronate (Fosamax) in 35- and 70-mg tablets have now been approved by the FDA and are being heavily promoted for prevention and treatment of postmenopausal osteoporosis. A new formulation of risedronate (Actonel) for once-a-week use is under development and may be available next year.

Many drugs are now marketed for prevention and treatment of postmenopausal osteoporosis. All regimens should include an adequate intake of calcium and vitamin D.

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).