Prescrition Drug Therapies

OBJECTIVE
To characterize the changes in bone mass with age in women and men, explain the physiology and pathophysiology of the bone remodeling process, identify the targets for prescription osteoporosis drugs in this process, and provide details about the uses, efficacy, safety, and economics of prescription drug therapies for osteoporosis prevention and treatment.


BACKGROUND
Preventing accelerated bone loss and decreasing age-related decreases in bone density are the primary goals of prescription drug therapy for osteoporosis. Bisphosphonates are the drugs of choice for preventing and treating postmenopausal osteoporosis. Alternatives for patients who cannot take bisphosphonates include raloxifene and calcitonin salmon.


SUMMARY
Menopause is accompanied by a rapid loss in bone mass that is followed by annual losses due to aging in women, which are similar to age-related bone mass decreases in men. Most prescription drug therapies for osteoporosis prevention or treatment reduce bone resorption by inhibiting osteoclast activation and activity, with only one medication class able to increase bone formation by stimulating osteoblasts. Denosumab, an investigational monoclonal antibody that inhibits nuclear factor kB ligand, would be a new class of anti-resorptive medications. Bisphosphonates currently are the drugs of choice for preventing and treating osteoporosis, with 7- and 10-year safety data available for risedronate and alendronate, respectively. Weekly and monthly regimens of bisphosphonates improve patient acceptance. Recently, an injectable form of ibandronate received U.S. Food and Drug Administration approval for once every 3 months administration. Raloxifene and calcitonin salmon are alternatives for patients who cannot take bisphosphonates because of contraindications or adverse effects. Teriparatide, a recombinant parathyroid hormone fragment, not only increases bone mineral density but also increases bone connectivity.


CONCLUSIONS
Osteoporosis medications are usually safe, especially if used correctly with proper patient education. Treating osteopenia has not been found to be cost effective in women. However, obtaining a dual-energy X-ray absorptiometry scan and treating osteoporosis has resulted in cost savings in senior women living in community and nursing home residences. Pharmacists have multiple opportunities for preventing and treating osteoporosis.

P revention of postmenopausal osteoporosis should begin during childhood because bone mass increases during the first 3 decades of life, reaching a peak at around the age of 30 years. 1 Men achieve a higher peak bone mass than women. 2 A slow loss of bone mass begins in both sexes when a person is in her or his mid-30s ( Figure 1). 3 A rapid loss of bone mass occurs after menopause in women because of estrogen deficiency. 4 Women experience a loss of 10% to 25% of bone mass in the decade after menopause. 2 Age-related bone loss begins 10 to 15 years after menopause in women and at about the age of 55 years in men. 2 Age-related bone loss occurs at a similar rate in women and men. 2 The goals of interventions to prevent and treat osteoporosis depend on a patient' s life stage (i.e., age) and gender. 2 In both sexes, maximizing peak bone mass is sought during childhood and adolescence, and preserving bone mass by avoiding bone loss is the goal in adulthood in men and from young adulthood until menopause in women. During menopause and the early postmenopausal period, efforts are directed toward preventing the accelerated bone loss that typically occurs during this period. Prevention of further bone loss is the goal in men after the age of 55 years and from late postmenopausal period thereafter in women. In senior citizens of both sexes, prevention of falls and fractures is an additional key goal, especially in persons with a low bone mass. s ss s B Bo on ne e P Ph hy ys si io ol lo og gy y a an nd d P Pa at th ho op ph hy ys si io ol lo og gy y receptors on osteoclasts, thereby preventing differentiation of osteoclasts and thus inhibition of bone resorption. 4 Estrogen stimulates osteoblasts and inhibits osteoclasts. 4,5 Various conditions, diseases, medications, and aging can perturb normal bone remodeling. Menopause is associated with estrogen deficiency and thus opposing effects to premenopausal estrogen sufficiency. Diseases and medications can have multiple deleterious effects from decreasing gut calcium absorption to accelerating bone loss. Bone loss due to normal aging is a function of inadequate bone formation in addition to other aspects of aging, such as poor diet, comorbid conditions, and medications. Prescription drugs used to prevent or treat postmenopausal osteoporosis act on various parts of the bone remodeling process. They vary by U.S. Food and Drug Administration (FDA) approvals for prevention and/or treatment (Table 1). Since efficacy with osteoporosis medications was generally studied concomitantly with calcium or calcium and vitamin D, these supplements should probably be used in combination with osteoporosis medications. Bisphosphonates decrease osteoclast function by inhibiting osteoclast formation, recruitment, survival, and adherence to bone. 2 Etidronate, a first-generation bisphosphonate, is rarely used for the prevention or treatment of osteoporosis because the drug is associated with osteomalacia. 2 It is not approved by the FDA for osteoporosis indications. Alendronate, a more potent oral secondgeneration agent, was the first bisphosphonate approved by the FDA. 7 Pamidronate, another second-generation injectable bisphosphonate, is not approved by the FDA for the prevention or treatment of osteoporosis. Oral risedronate, oral and injectable ibandronate, and injectable zoledronic acid (investigational for osteoporosis) are third-generation bisphosphonates with greater potency than second-generation agents. 8 The binding affinities of bisphosphonates differ (in descending order from highest to lowest binding affinity, they are zoledronic acid, alendronate, ibandronate, risedronate, and etidronate), with possible implications for drug persistence in bone and longer duration of action. 9 www.amcp.org Vol. 12

Prescription Drug Therapies for Prevention and Treatment of Postmenopausal Osteoporosis
Selective estrogen receptor modulators (e.g., raloxifene) act as agonists at estrogen receptors on both osteoblasts and osteoclasts. 2 Calcitonin salmon acts directly on osteoclast receptors to suppress their activity. 5 Denosumab mimics the action of osteoprotegerin by turning off osteoclast activity and is investigational. 10 Postmenopausal estrogen therapy (ET) appears to directly inhibit osteoclasts and is approved for prevention although with limited use after the Women' s Health Initiative trials. 5 Although bone resorption is associated with hyperparathyroidism and large doses of parathyroid hormone, smaller doses increase osteoblast differentiation and activity. These latter effects are achieved with teriparatide, a recombinant human parathyroid hormone fragment, 11 and investigational PTH 1-84. 12 Several investigational agents are being explored to inhibit other aspects of resorption and to enhance other aspects of formation. Investigational osteoporosis drug classes include integrin receptor antagonists, cathepsin K inhibitors, recombinant human insulin-like growth factor 1, H+ATPase inhibitors, interleukin-1 receptors, calciometrics, and calciolytics. 6 Efforts to develop compounds with the characteristics of osteoprotegerin that bind to the RANK receptor and inhibit osteoclast activation have not been successful because of antibody formation. s ss s T Tr re ea at tm me en nt t A Al lg go or ri it th hm m Bone mineral density (BMD) testing (see the preceding article by Kamel in this supplement) of the spine and hip is appropriate before initiating treatment with prescription osteoporosis medications in women aged 65 years and older, women aged 60 to 64 years who are at increased risk for osteoporotic fractures, and men at increased risk for fractures ( Figure 1). 2     osteoporosis medications may be considered without first testing for BMD in men and women with a fragility fracture or using systemic glucocorticoids on a long-term basis. 2 A Z-score less than -2.0 (see the preceding article by Kamel in this supplement) suggests the need for a diagnostic work-up to identify a secondary cause of osteoporosis. Drug therapy is not indicated for patients with a normal BMD (a T-score >-1), and its use is controversial in patients with osteopenia (a T-score between -1 and -2.5) and most likely is not cost effective. 13 BMD testing should be performed every 1 to 5 years in patients with normal BMD or osteopenia. 2 If a patient has spinal osteoporosis (i.e., a spine T-score <-2.5), a bisphosphonate, raloxifene, or calcitonin salmon could be tried, in that order. All of these therapies have been shown to decrease vertebral fractures, but only the bisphosphonates have been shown to decrease the incidence of hip fractures. 2 Therefore, if hip osteoporosis is present (i.e., a hip T-score <-2.5), treatment with a bisphosphonate is preferred. If the patient is intolerant to oral bisphosphonates, a parenteral bisphosphonate, teriparatide, raloxifene, and calcitonin salmon are alternatives. 2 s ss s B Bi is sp ph ho os sp ph ho on na at te es s

Medications Approved by the FDA for Prevention and Treatment of Osteoporosis
Bisphosphonates are the drugs of choice for preventing and treating osteoporosis. 2 The drugs increase BMD in a dosedependent manner, and they produce significant reductions in the risk of hip, spine, and nonvertebral fractures. 2,14-17 The efficacy of bisphosphonates has been demonstrated in both women and men, including the elderly. 2 The response to bisphosphonates is greater in patients with a low BMD than in patients with a high BMD. 17 The increase in BMD from bisphosphonates is enhanced by concomitant ET or raloxifene 2 but is inhibited by concomitant PTH/teriparatide therapy. Adequate calcium and vitamin D intake is also needed for the beneficial effects of bisphosphonates to be observed.
Bisphosphonates can irritate the upper gastrointestinal (GI) mucosa, but the drugs are relatively safe if the patient has no serious underlying GI disorders. Bisphosphonates should not be used in patients with esophageal strictures or achalasia or for those who are unable to stand or sit upright for at least 30 minutes (at least 60 minutes for ibandronate) after drug administration. 7,[18][19][20] Bisphosphonates may be used in patients with gastroesophageal reflux disease and patients who take aspirin or nonsteroidal antiinflammatory drugs. Nausea, abdominal pain, and dyspepsia are the most common adverse effects from bisphosphonates. 2 Esophageal perforation and bleeding are rare. Switching to a formulation that is administered weekly or monthly instead of daily might minimize these effects. The cells that line the GI tract regenerate in about 5 days, with the longer dosing intervals allowing for cellular regeneration between doses. 2 Osteonecrosis of the jaw has been infrequently reported in patients receiving bisphosphonates (particularly with the injectable agents pamidronate and zoledronic acid), primarily in patients receiving chemotherapy or corticosteroids or in associa-tion with tooth extraction, surgery, or infection. 7,[18][19][20][21][22] Muscle, bone, and joint pain that usually abates after discontinuing the drug and a flu-like syndrome, with fever, chills, flushing, and musculoskeletal pain, also have been reported. 7,[18][19][20]22 Bisphosphonates should not be used in patients with severe renal impairment (creatinine clearance less than 30 mL/min) because of a lack of data. 7,18-20 A Al le en nd dr ro on na at te e Long-term efficacy and safety data are available from more than 10 years of alendronate use. Progressive increases in spine and hip BMD were observed over a 10-year period in a randomized, double-blind study of 247 postmenopausal women with osteoporosis who received the bisphosphonate alendronate 5 mg/day or 10 mg/day. 23 The greatest increases in BMD were observed during the first 3 to 5 years of treatment and with the 10-mg dose. A tendency to reach a plateau in hip BMD was observed after about 5 years, but progressive increases in spine BMD continued throughout the 10-year period. The 10-year increases in BMD from baseline after 10 mg per day for 10 years was 13.7% for lumbar spine, 10.3% for trochanter, 5.4% for femoral neck, and 6.7% for proximal femur.
The increased BMD from bisphosphonate therapy is maintained or slightly diminished after discontinuation of the drug but is better than placebo therapy. The effects on spine and hip BMD from alendronate 2.5 to 20 mg daily for 2, 4, or 6 years followed by no treatment for 7, 5, or 3 years, respectively, were evaluated in a placebo-controlled study of 203 postmenopausal women. 24 The rate of bone loss after all doses of alendronate discontinuation was comparable to the rate observed with placebo, thus due to normal aging, not related to a drug-induced accelerated rate of bone loss such that is seen with ET discontinuation. A benefit from alendronate over placebo was observed for up to 7 years after discontinuation of the drug. This study provides valuable information about duration of therapy, but no there is no consensus yet on how long to continue bisphosphonate therapy or at what point to reinitiate therapy.

R Ri is se ed dr ro on na at te e
Clinical trials have also documented long-term (up to 5 years) BMD efficacy and safety with risedronate. In a 1-year randomized, double-blind study of 1,053 women with postmenopausal osteoporosis (Fosamax Actonel Comparison Trial [FACT]), the efficacy of once-weekly risedronate (35 mg) and once-weekly alendronate (70 mg) in increasing BMD was compared. 25 Significantly greater increases in BMD were observed with alendronate than with risedronate. The differences measured in the BMD were 1.4% for hip trochanter (P <0.001), 1.0% for total hip (P <0.001), 0.7% for femoral neck (P <0.01), and 1.2% for lumbar spine (P <0.001). However, the clinical significance of these findings cannot be extrapolated to a difference in the impact of the drugs on fractures. This study most likely will never be conducted because of the large number of patients required. With the evolving science of bone remodeling and osteoporosis, a medication' s impact on bone structure will most likely become more important than BMD changes only.
In a 2-week study of 515 healthy, postmenopausal women, risedronate 5 mg/day was associated with a significantly lower risk of gastric ulcers than alendronate 10 mg/day, 4.1% versus 13.2%, respectively (P <0.001), potentially because of differences in the GI damage from pyridinyl bisphosphonates (e.g., risedronate) and amino bisphosphonates (e.g., alendronate). 26 Comparative studies over a longer duration and with weekly therapy are needed to determine whether the risk of upper GI adverse effects from these bisphosphonates differs clinically.

I Ib ba an nd dr ro on na at te e
Ibandronate is the newest bisphosphonate to reach the market. It is unique among bisphosphonates because it may be given orally on a monthly or daily basis or as a quarterly injection. Potential advantages of an injectable bisphosphonate formulation include a lower risk of GI adverse effects because of less irritation of the GI mucosa and improved bioavailability and patient adherence. Although the use of the injectable route of administration is not as convenient and is more costly than the oral route, it might be preferred in patients in a long-term-care setting who cannot remain sitting or standing for at least 30 to 60 minutes after drug administration or in patients with GI diseases in whom oral therapy is contraindicated.
The efficacy of oral ibandronate 2.5 mg/day with calcium 500 mg and vitamin D 400 units in reducing the risk of fractures was demonstrated in a pivotal, 3-year, randomized, double-blind, placebo-controlled, parallel-group study of 2,946 postmenopausal women with osteoporosis. 17 Ibandronate produced significantly greater increases from baseline in lumbar spine (6.5% vs. 1.3%, respectively; P <0.0001) and hip BMD (3.4% vs. -0.7%, respectively; P <0.0001) than placebo. The rate of new vertebral fractures was 4.7% with ibandronate and 9.6% with placebo, representing a 62% reduction (P = 0.0001) in fractures with the bisphosphonate treatment. Ibandronate produced a significant 49% reduction (P=0.0117) in clinical vertebral fractures (i.e., fractures confirmed by X-ray and accompanied by pain), representing an absolute difference of 2.5%. The incidence of nonvertebral fractures was similar with ibandronate (9.1%) and placebo (8.2%). However, in a post hoc analysis of a subset of high-risk patients with a particularly low femoral neck BMD (T-score <-3.0), ibandronate therapy was associated with a significantly lower incidence of nonvertebral fractures than placebo (about 7.5% vs. 14.8%, respectively; 69% relative risk reduction, P = 0.013). The incidence of adverse drug reactions was similar with ibandronate (20%) and placebo (18%).
The efficacy of using a monthly dose of ibandronate instead of a daily dose for treating postmenopausal osteoporosis was demonstrated in a 2-year, randomized, double-blind, phase 3, noninferiority trial known as the Monthly Oral Ibandronate in Ladies (MOBILE) study. 27 Several monthly doses (100 mg as 2 divided doses on 2 consecutive days, 100 mg on a single day and 150 mg on a single day) were compared with 2.5 mg/day in 1,609 women with postmenopausal osteoporosis. The women also took supplements (calcium 500 mg and vitamin D 400 units) daily. After 1 year of treatment, all of the monthly ibandronate doses were judged noninferior to the daily dose for increasing lumbar spine, hip, femoral neck, and trochanter BMD, with the greatest increases from baseline in the monthly 150-mg dose group. The incidence of adverse effects leading to withdrawal from the study was similar with monthly drug administration (5.1%-6.3%) and daily therapy (7.3%).
Ibandronate 3 mg intravenous (IV) every 3 months and 2.5 mg/day orally were compared in a double-blind, double-dummy, phase 3 study of 1,395 women with postmenopausal osteoporosis (Dosing IntraVenous Administration [DIVA] study). 28 Calcium (500 mg/day) and vitamin D (400 units/day) supplements were provided to all women. After 1 year of treatment, significantly greater increases from baseline in lumbar spine BMD were associated with IV therapy (4.8%) than with oral therapy (3.8%; P <0.001). Increases in total hip, femoral neck, and trochanter BMD also were greater with IV therapy than oral therapy.
Patient preferences for weekly alendronate 70-mg doses or monthly ibandronate 150-mg doses were evaluated in a 6-month, prospective, randomized, open-label study of 342 women with postmenopausal osteoporosis (Boniva Alendronate Trial in Osteoporosis [BALTO] study). 29 A 2-period, 2-sequence crossover treatment design was used. Significantly more women (66%) preferred monthly ibandronate therapy than weekly alendronate therapy (27%; P <0.0001)). Seven percent of participants had no preference for either drug or dosing frequency. Greater tolerability of adverse effects was a reason for 17% of patients who preferred monthly ibandronate and 4% of patients who preferred weekly alendronate. The incidence of adverse effects was similar, with approximately 12% of both groups reporting GI adverse effects.

Z Zo ol le ed dr ro on ni ic c A
Ac ci id d Zoledronic acid (zoledronate), a potent, third-generation injectable bisphosphonate, is currently approved by the FDA for bone metastasis and malignant hypercalcemia and investigational for the prevention or treatment of osteoporosis. The effects of 5 different IV zoledronic acid regimens on BMD were evaluated in a 1-year, randomized, double-blind, placebo-controlled study of 351 postmenopausal women with low BMD. 30 Zoledronic acid 0.25 mg, 0.5 mg, or 1 mg or placebo were given at 3-month intervals. A fifth group received a single 4-mg dose, and the sixth group received two 2-mg doses 6 months apart. All 5 zoledronic acid regimens produced significantly greater but somewhat similar BMD increases from baseline compared with the mean placebo group response in lumbar spine (4.3 to 5.1% greater response, P <0.001) and femoral neck BMD (3.1 to 2.5% greater response, S14 Supplement to Journal of Managed Care Pharmacy JMCP July 2006 Vol. 12, No. 6, S-a www.amcp.org Prescription Drug Therapies for Prevention and Treatment of Postmenopausal Osteoporosis P <0.001). All zoledronic acid regimens suppressed biochemical markers of bone resorption to a significantly greater extent than placebo throughout the study. The incidence of myalgia and pyrexia was higher in the zoledronic acid groups than in the placebo group. Treatment related side effects were 45% to 67% in the zoledronic acid groups versus 27% in the placebo group (P <0.05); however, the treatment-related dropout rates for zolendronic acid (3% to 7%) were similar to the placebo group (2%).

s ss s P Pa at ti ie en nt t E Ed du uc ca at ti io on n
Patient education is vital for the safe and effective use of bisphosphonates to prevent and treat osteoporosis. The bioavailability of oral bisphosphonates is low, and food and beverages other than plain water can further reduce bioavailability. Therefore, patients should be advised to take the medication at least 30 minutes before the first food or beverage (other than plain water) of the day, and take the medication only with a full (6-8 oz.) glass of plain water (not mineral water, orange juice, coffee, sodas, or milk). 7,[18][19][20] Patients also should be advised not to lie down for at least 30 minutes (60 minutes for ibandronate) after taking the medication to facilitate delivery to the stomach and reduce the risk for esophageal irritation. 7,18-20 Calcium and other multivalent cations, including antacids, calcium supplements, and multivitamins, should be taken at least 60 minutes after the bisphosphonate because the cations may interfere with bisphosphonate absorption. 7,[18][19][20] Patients also should be warned to report difficult or painful swallowing or heartburn to their health care provider. Patient counseling should be ongoing and adherence to therapy should be assessed often. To improve adherence with the once-monthly ibandronate regimen, patients have the option of receiving reminders by regular or electronic mail from the manufacturer (www.myboniva.com). Although a 30-minute fast is recommended, longer fasts could increase bisphosphonate absorption, according to an alendronate pharmacokinetic study 31 and a recent ibandronate study. 32 The impact on efficacy of changing the duration of fasting after administration of oral ibandronate 2.5 mg/day from 60 minutes to 30 minutes was evaluated in a 48-week, multicenter, open-label, randomized, parallel-group, noninferiority study of 184 women with postmenopausal osteoporosis. 32 The relative increase from baseline in lumbar spine BMD was lower in the 30-minute fast group (3%) than that in the 60-minute fast group (5%). The increase in total hip BMD also was lower with the 30-minute fast than with the 60-minute fast (2% vs. 3%, respectively). Thus, a 30-minute fast did not meet the criteria for noninferiority to a 60-minute fast, so a 60-minute fast is recommended after oral administration of ibandronate. 20 Ibandronate injection should be administered by health care professionals who have been educated regarding the unique requirements for handling and administering the medication. Ibandronate injection is provided in a kit with a single-use, prefilled, glass syringe containing 3 mg/3 mL of the drug, with a 23-gauge, 1-inch needle and an alcohol wipe. The kits should be stored at controlled room temperature (59°F-86°F). Reconstitution and refrigeration of the drug are not required. The drug should not be mixed with calcium-containing solutions or other IV medications. Ibandronate injection is administered by rapid IV injection over 15 to 30 seconds, using caution not to give it intra-arterially. Treatment with IV bisphosphonates has been associated with renal toxicity, with a risk that appears to be inversely related to the rate of drug administration. The rapid injection of ibandronate over 15 to 30 seconds was not associated with acute renal failure in controlled clinical trials. 33 Raloxifene acts as an estrogen agonist in bone and on lipids and as an estrogen antagonist in breast and uterine tissues. 34 Raloxifene increases spine and hip BMD, but not to the same extent as bisphosphonates or ET. 2,3 Raloxifene reduces the risk of vertebral fractures by 30% to 50% in women with postmenopausal osteoporosis, but it does not affect the rate of nonvertebral fractures. 5,[35][36][37][38] Adding raloxifene to alendronate does not produce greater increases in BMD than using alendronate alone; however, combination therapy is better than raloxifene alone. 37 Whether changes in BMD predict an impact on fractures from raloxifene therapy is not clear since fracture prevention does not correlate with BMD changes for this medication.
To determine if raloxifene had a cardiovascular effect and could add additional benefit during osteoporosis therapy, its effects on lipids and cardiovascular disease and mortality have been evaluated. Decreases in total and low-density lipoprotein cholesterol concentrations with little change in high-density lipoprotein cholesterol and triglyceride concentrations are associated with raloxifene therapy, which are lower than those achieved with ET/hormone therapy (HT). 38 Unlike ET, raloxifene is not associated with negative cardiovascular events. A secondary analysis of cardiovascular event data (i.e., coronary and cerebrovascular events, including myocardial infarction, unstable angina, coronary ischemia, stroke, and transient ischemic attack) from the Multiple Outcomes of Raloxifene Evaluation (MORE) trial revealed that raloxifene treatment over a 4-year period did not significantly affect the risk of cardiovascular events. 39 However, in a subset of women who were at increased risk for cardiovascular events because of the presence of multiple cardiovascular risk factors, a history of coronary events, or a prior revascularization procedure, raloxifene significantly reduced the risk of cardiovascular events compared with placebo. Preliminary data from the Raloxifene Use for The Heart trial (RUTH) found no increases or decreases in heart disease or mortality with raloxifene (newsroom.lilly.com/ReleaseDetail.cfm? ReleaseID=192692).
Raloxifene' s role in osteoporosis therapy could change, at least for a subset of women with or at risk for breast cancer, if it were to receive an FDA approval for breast cancer prevention. The effect of raloxifene on the risk for breast cancer was evaluated in the MORE study. 40 In this randomized, double-blind trial, 7,705 women with postmenopausal osteoporosis received raloxifene 120 mg/day or 60 mg/day or placebo and were followed for a median of 40 months. Raloxifene significantly reduced the incidence of invasive breast cancer by 76%, with 126 the number of women needed to treat to prevent 1 case of breast cancer (relative risk reduction changed from 4.3 on placebo to 1.5 with raloxifene). Raloxifene did not increase the risk of endometrial cancer; it increased the risk of venous thromboembolic disease 3-fold, but the incidence was still low (18 cases in 2,557 women).
Raloxifene 60 mg is taken orally once daily. The drug causes hot flushes in as many as 1 in 4 women. 38 Raloxifene is associated with an increased risk of thromboembolism (e.g., deep vein thrombosis), although the incidence is low and it is contraindicated in women with a history of venous thrombosis. 38 s ss s H Ho or rm mo on ne e T Th he er ra ap py y HT (estrogen plus a progestin or, for women without a uterus, estrogen alone [ET]) increases BMD in women with or at risk for postmenopausal osteoporosis. 41 A reduced risk for vertebral and hip fractures has been reported in postmenopausal women receiving estrogen plus a progestin, and a reduced risk of hip fractures has been observed in postmenopausal women who received estrogen alone. [42][43][44] However, the use of HT to prevent and treat osteoporosis has fallen out of favor because of the findings from the Women' s Health Initiative and other research suggesting an increased risk of stroke and cardiovascular disease early in the course of therapy in patients receiving HT or ET. 43,44 The risks outweigh the benefits of ET or HT in most women, although ET or HT is still approved by the FDA for the prevention (not treatment) of postmenopausal osteoporosis in women who are at significant risk and for whom nonestrogen medications are not appropriate. 45 HT is still advocated for short-term use to manage vasomotor and urogenital symptoms associated with menopause. The lowest effective dose should be used.

s ss s C Ca al lc ci it to on ni in n S Sa al lm mo on n
Calcitonin is a natural polypeptide hormone secreted by the thyroid gland in response to high serum calcium concentrations. It decreases bone resorption. Calcitonin salmon is a synthetic form with the same amino acid sequence as that of calcitonin of salmon origin. Calcitonin salmon is approved for the treatment (but not prevention) of postmenopausal osteoporosis in women who are more than 5 years beyond menopause and have a low bone mass. 46,47 The drug is available as an injection for subcutaneous (SC) or intramuscular administration and a nasal spray. The injectable form is seldom used because it can cause nausea and facial flushing and the nasal spray is better tolerated. 5 Calcitonin salmon nasal spray 200 units/day decreased the risk of new vertebral fractures by about one third (18% vs. 26%, respectively; P = 0.03) in a large, 5-year study of postmenopausal women with osteoporosis. 48 Of note, the withdrawal rate in this study was 59%. However, the drug does not appear to decrease the risk of hip fractures. There is evidence of a plateau in the effect of calcitonin salmon on markers of bone resorption after 8 weeks of treatment, suggesting that intermittent administration may be appropriate. 49 Further study is needed.
An analgesic effect from intranasal calcitonin salmon has been reported in patients with osteoporotic vertebral fractures. 50,51 The time to onset of analgesia is as little as 1 week. 51 Analgesia might be the result of endorphin release, an anti-inflammatory effect due to decreased prostaglandin synthesis, direct calcitonin receptor stimulation, or decreased osteoclastic activity. 51,52 The analgesic effect from calcitonin salmon may reduce the requirements for analgesic medications. 51 Rhinitis and epistaxis are the most common adverse effects from calcitonin salmon nasal spray. 46 The spray is given as a single daily 200-unit dose. Patients should be instructed to alternate nares daily.
Unopened bottles of calcitonin salmon nasal spray should be stored in the refrigerator, but the bottle in use may be stored at room temperature for up to 35 days. 46 Patients should be instructed how to prime the pump before the first dose, but priming is not required for subsequent doses. s ss s T Te er ri ip pa ar ra at ti id de e Teriparatide (recombinant human PTH) contains the first 34 amino acids of the 84 amino acids in human PTH. It is administered as a single daily dose by SC injection into the thigh or abdominal wall. 53 A recombinant human PTH product with all 84 amino acids might be approved by the FDA for the treatment of postmenopausal osteoporosis in the near future. Administration of this product by the SC route also appears to increase BMD and reduce the risk of vertebral fractures. 11 At therapeutic doses, teriparatide increases bone formation by stimulating osteoblast replication and inhibiting osteoblast apoptosis. 5 Teriparatide increases the thickness of outer cortical bone and increases the connectivity of trabecular bone (the interior porous bone found in vertebrae and other bones). 54 These changes increase bone strength and make teriparatide unique among osteoporosis therapies. Although bisphosphonates increase BMD, they do not affect connectivity or strength. Increases in lumbar spine BMD of 9.7% (P <0.001) and femoral neck of 2.8% (P <0.001) were significantly greater than placebo. 55 Teriparatide significantly reduced the risk of new vertebral (5% vs. 14%, respectively; relative risk 0.35; 95% confidence interval [CI], 0.22-0.55) and nonvertebral fragility fractures (3% vs. 6%, respectively; relative risk 0.47; 95% CI, 0.25-0.88) compared with placebo in postmenopausal women with osteoporosis.
Teriparatide may be used in conjunction with raloxifene or HT. However, teriparatide should not be used in combination with bisphosphonates because they may reduce the effects of teriparatide. 56,57 Bisphosphonates can be used before or after PTH therapy, with potentially better results in bisphosphonate-naïve patients receiving the bisphosphonate after PTH therapy.
Teriparatide can cause orthostatic hypotension, so patients should be advised to position themselves so that they can sit or lie down if they feel lightheaded after drug administration. Such reactions usually resolve within a few minutes to a few hours and do not preclude continued use of the drug. 53 Large doses of teriparatide were associated with an increased incidence of osteosarcoma in animal studies, but the relevance of these findings for humans are questionable. Osteosarcoma has not been observed in humans in phase 4 postmarketing surveillance. Teriparatide should not be used for more than 2 years because the safety and efficacy of the drug for periods longer than 2 years have not been evaluated. 53 Patient counseling should address the proper storage and administration of teriparatide. The drug is a clear, colorless, 250-mcg/mL solution provided in prefilled pens containing twentyeight 20-mcg doses. Teriparatide may be self-administered by the patient or a caregiver once she or he receives instructions on proper priming and use of the pen. The drug should be stored under refrigeration (36°F -46°F) and administered without allowing it to warm to room temperature. 53 The pen should be recapped between uses. Missed doses should be administered as soon as they are remembered, but no more than 1 injection should be administered on the same day. 53 s ss s D De en no os su um ma ab b Denosumab (formerly known as AMG 162) is a humanized monoclonal antibody specific for the RANK ligand. It inhibits osteoclast activation and activity. 58 The efficacy and safety of denosumab were evaluated in a 12-month, phase 2, randomized, controlled trial of 412 postmenopausal women with low BMD. 59 Subjects were randomly assigned to receive denosumab 6 mg, 14 mg, or 30 mg SC every 3 months; denosumab 14 mg, 60 mg, 100 mg, or 210 mg SC every 6 months; open-label alendronate 70 mg orally once weekly; or placebo. All patients received calcium and vitamin D supplementation. Denosumab produced increases in lumbar spine (3.0%-6.7%), total hip (1.9%-3.6%), and distal radius (0.4%-1.3%) BMD that exceeded those produced by placebo (P <0.001) and were comparable to or greater than those produced by alendronate (4.6%, 2.1%, -0.5%, respectively. However, small increases in risk for neoplasm (1.9%) and infection (1.0%) were associated with denosumab treatment compared with alendronate (0% for both) or placebo (0% for both). Additional denosumab safety data are needed. Phase 3 clinical trials of denosumab in postmenopausal women with osteoporosis began in 2004.

s ss s E Ec co on no om mi ic cs s
Prescription osteoporosis drug therapies (e.g., bisphosphonates, raloxifene, calcitonin salmon, teriparatide) are more costly than nonprescription calcium and vitamin D supplements, most of which cost $5 to $15 per month. The monthly cost of prescription osteoporosis drugs ranges from a low of about $85 for oral bisphosphonates to a high of around $700 for teriparatide. The monthly costs of raloxifene and calcitonin salmon are slightly higher than the oral bisphosphonates. The cost of ibandronate injection is higher than that of oral bisphosphonates, including oral ibandronate, but the greater tolerability might justify the added expense. The high cost of teriparatide might be justified because it is the only osteoporosis drug that increases bone formation and connectivity. Depending on the Medicare Part D plan, usually alendronate or risedronate are covered with varying copays per plan for preferred medications since generic agents are not available. Ibandronate is either at equal bisphosphonate coverage or at the nonpreferred or higher tier copay. Raloxifene and calcitonin salmon are covered at the preferred or middle tier copay. Teriparatide is usually listed as nonpreferred or in the highest tier copay, and prior authorization is often required. A Markov cost-utility analysis of the benefit of alendronate (compared with no treatment) in postmenopausal women with osteopenia (i.e., at risk for osteoporosis, T-score -1.5 to -2.4) was performed from a societal perspective. 13 Five years of alendronate therapy was assumed because of the plateau in effect on hip BMD after this duration of treatment. 23 The analysis used fracture data from the Fracture Intervention Trial, a randomized, blinded, placebo-controlled trial of alendronate. 60   Prescription Drug Therapies for Prevention and Treatment of Postmenopausal Osteoporosis ages and 3 different femoral neck T-scores ( Table 2). The investigators concluded that alendronate therapy is not cost effective in any of these scenarios, assuming a societal willingness to pay $50,000 per QALY. However, the results of the cost-utility analysis changed when the influence of additional risk factors for fracture other than low BMD (e.g., a family history of fractures) was assessed for 65-year-old postmenopausal women with osteopenia and a T-score of -2.0. As the relative risk for fracture (adjusted for BMD) from added risk factors increased, the cost per QALY decreased. Alendronate treatment became cost effective (i.e., the cost per QALY fell below $50,000) for these patients when the relative risk for fractures reached 2.0 or higher (i.e., a 2-fold or greater increase in the relative risk for fracture). The World Health Organization currently is analyzing risk factors for fracture that will facilitate cost-effectiveness analyses and patient selection for therapy in the future.
A similar cost-utility model was developed by the same investigators to evaluate the cost-effectiveness from a societal perspective of universal bone densitometry screening measurements in women aged 65 years or older followed by 5 years of alendronate treatment in those with a femoral neck T-score of -2.5 or lower (i.e., a diagnosis of osteoporosis). 61 The cost per QALY gained by using alendronate instead of no treatment was $43,000 for women aged 65 years and $5,600 for women aged 75 years. In women aged 85 years living in nursing homes, the cost per QALY gained from alendronate therapy was $7,300 to $12,900. Alendronate was cost saving for women aged 85 and 95 years living in the community (i.e., ambulatory) and women aged 95 years living in nursing homes. Thus, universal bone densitometry screening for women aged 65 years or older and the use of alendronate therapy for women with osteoporosis were cost effective.
s ss s C Co on nc cl lu us si io on n Preventing the accelerated bone loss associated with the early postmenopausal period and decreasing aging-related decreases in bone density are the primary goals of prescription osteoporosis drug therapy. Bisphosphonates are the drugs of choice for preventing and treating postmenopausal osteoporosis. Increasing the dosing interval might increase patient acceptance and adherence by improving convenience. Alternatives for patients who cannot take bisphosphonates include raloxifene and calcitonin salmon. Teriparatide is used to build new bone in patients with significant osteoporosis and should not be used concomitantly with a bisphosphonate. The costeffectiveness of osteoporosis drug therapies depends on patient age, BMD, and other risk factors for the disease; however, treating osteoporosis with a bisphosphonate in senior women is cost effective and using it to prevent preventing osteoporosis in women with osteopenia is not.

DISCLOSURES
This article is based on the proceedings of a symposium held on April 6, 2006, at the Academy of Managed Care Pharmacy' s 18th Annual Meeting and Showcase in Seattle, Washington, which was supported by an independent educational grant from Roche Laboratories and GlaxoSmithKline. The author received an honorarium from Roche Laboratories and GlaxoSmithKline for participation in the symposium. She discloses that she received a research grant from Merck.