- CONDITION CENTERS
Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.
Osteoporosis (porous bone) is a disease that causes low bone density and structural deterioration of the bone tissue, causing fragility of the bone and an increased risk of hip, spine, and wrist fractures.1 This condition affects an estimated 10 million people in the United States older than age 50; 80% are women.1,2 Another estimated 34 million people have osteopenia (low bone mass), which is a risk factor for the development of osteoporosis.1,2
Women are more susceptible to osteoporosis, have a lower peak bone mass and smaller bones than men, and lose bone at a much more accelerated pace than men in middle age because of the reduction of estrogen levels during menopause.1 In addition, women may lose up to 20% of their bone mass in the first 5 to 7 years after menopause.1,2
It is estimated that osteoporosis is responsible for >1.5 million fractures annually, including an estimated 300,000 hip fractures, 700,000 vertebral fractures, 250,000 wrist fractures, and >300,000 fractures at other sites.1,3 In general, the average woman has obtained 98% of her skeletal mass by age 20; therefore, increasing awareness of the importance of strong bones during the early years may be beneficial to decreasing one's risks of osteoporosis.3
Osteoporosis is commonly known as a silent disease because no symptoms are present in the early disease stages; however, in the later stages, a patient may initially experience fractures of the vertebrae, wrists, or hips and other symptoms that may include the following1,2,4:
Various nonmodifiable and modifiable risk factors are associated with an increase incidence of osteoporosis.1,2,4-6
The long-term use of certain medications also can cause bone loss and an increased risk of osteoporosis. Examples include heparin, some anticonvulsants, aromatase inhibitors, antacids containing aluminum, corticosteroids, gonadotropin-releasing hormone agonists used for treating endometriosis, lithium, methotrexate, and thyroxine.1-7 Patients with any concerns about the long-term use of these medications should be encouraged to discuss them with their primary health care provider.
Web sites on osteoporosis:
Diagnostic tests for osteoporosis include bone mineral density tests to measure bone density in various parts of the body. The most common test used is a dual-energy x-ray absorptiometry (DXA) test. A DXA test can detect osteoporosis before a fracture occurs, predict the chances of a fracture occurring, confirm a diagnosis of osteoporosis, ascertain the rate of bone loss, and assess the effects of the chosen therapy.1,2,4,6
The main goal in treating osteoporosis is to prevent fractures. Although no cure exists for osteoporosis, several FDA-approved pharmacologic agents exist for treating or preventing osteoporosis. These pharmacologic agents include calcium and vitamin D, bisphosphonates, selective estrogen receptor modulators (SERMs), calcitonin-salmon, teriparatide, and hormone replacement therapy. Pharmacists have a crucial role in ensuring that patients are effectively counseled on the proper administration of these agents, the adverse effects associated with their use, and the importance of adhering to the prescribed therapy.
Patients should be encouraged to discuss the use of calcium and vitamin D supplementation with their primary health care provider to determine the amount of calcium that is adequate for their age group. The National Osteoporosis Foundation recommends that women have a daily intake of 1000 to 1300 mg of calcium and 400 to 800 international units of vitamin D, which should be obtained through diet, supplements, or both.8
The bisphosphonates include alendronate (Fosamax), alendronate with calcium (Fosamax D), risedronate (Actonel), risedronate with calcium (Actonel D), and ibandronate (Boniva). They are approved for both the prevention and treatment of postmenopausal osteoporosis. Alendronate also is approved to treat bone loss that results from glucocorticoid use and is approved for treating osteoporosis in men.1,9 In addition, risedronate is approved to prevent and treat glucocorticoid-induced osteoporosis and to treat osteoporosis in men.1,10
Alendronate is available in daily and weekly doses, and alendronate plus vitamin D is available in a weekly dose.9,11 Risedronate is available in daily and weekly doses, and risedronate with calcium is available in a weekly dose.1,10,11 Ibandronate is indicated for the prevention and treatment of postmenopausal osteoporosis in women and is available in a monthly oral dose and as an intravenous (IV) injection administered once every 3 months. The most common adverse effects associated with the injection include flu-like illness, headache, and bone, muscle, or joint pains.11,12
In August 2007, the FDA approved another bisphosphanate, zoledronic acid (Reclast), for the treatment of osteoporosis in postmenopausal women. Zoledronic acid is administered intravenously once a year, and once administered, it rapidly moves to bone and preferentially localizes at sites of high bone turnover.11,13 Reclast is supplied as 5 mg in a 100-mL, ready-to-infuse solution for IV administration. The recommended initial dose of the drug is a 5-mg infusion given intravenously over no less than 15 minutes once a year.13
Pharmacists should counsel patients to take oral bisphosphonates on an empty stomach with at least 6 to 8 oz of water upon waking in the morning, remain in an upright position, and not eat or drink anything (including other medications) for at least 30 minutes after administration. The manufacturer of ibandronate recommends waiting at least 60 minutes after administration. The use of bisphosphonates is contraindicated in patients with severe renal disease, hypocalcemia, or in patients with disorders of the esophagus.11 Common adverse effects of oral bisphosphonates include irritation of the upper gastrointestinal mucosa, nausea, dizziness, and headache.9,11,14
Raloxifene (Evista), which is classified as a SERM, is approved for the treatment and prevention of postmenopausal osteoporosis. Studies have shown it to prevent bone loss, have beneficial effects on bone mass, and reduce the incidence of spine fractures.1 This agent is taken once daily. The most common adverse effects associated with its use include hot flashes, sweating, thrombosis, muscle soreness, and weight gain.11,15
Calcitonin is a naturally occurring hormone involved in calcium regulation and bone metabolism and is approved for the treatment of osteoporosis in women who are at least 5 years beyond menopause. Calcitoninsalmon (Miacalcin) is currently available as a single daily nasal spray or as a subcutaneous injection. Although it does not affect other organs or systems in the body, injectable calcitonin may cause an allergic reaction and unpleasant side effects, including flushing of the face and hands, polyuria, nausea, and skin rash. Rhinorrhea is the only adverse effect reported with nasal calcitonin.11,16
Teriparatide (Forteo) is an injectable form of human parathyroid hormone. Its approved indications are for postmenopausal women and men with osteoporosis who are at high risk for having a fracture. Common adverse effects include nausea, dizziness, and leg cramps. Teriparatide is approved for use for up to 24 months.1,11,17
Estrogen/hormone therapy (ET/HT) has been shown to reduce bone loss, increase bone density in both the spine and hip, and reduce the risk of hip and spine fractures in postmenopausal women.1 ET/HT is approved for preventing postmenopausal osteoporosis, but not for the treatment of osteoporosis. It is most commonly administered in the form of a pill or skin patch. Adverse effects of ET/HT include vaginal bleeding, breast tenderness, mood disturbances, and thrombosis.1,11 The FDA recommends prescribing the lowest possible dose for the shortest time; estrogen should not be used unless a woman is at significant risk for osteoporosis and cannot use nonestrogen medications.1,11 It also is important to note that once therapy is stopped, bone loss will continue.
Pharmacists also can assist patients by recommending nonpharmacologic measures that also may be beneficial in preventing further complications or minimizing bone loss. These include exercising (eg, weight-bearing and resistance exercise), limiting caffeine intake, eating a balanced diet rich in calcium and vitamin D, not smoking, or limiting alcohol intake. In addition to counseling patients on key information concerning the medications prescribed for osteoporosis, pharmacists also can increase awareness of this condition and provide information on risk factors and preventive measures, particularly among younger women. Patients also should be advised to discuss their risks of osteoporosis with their primary health care provider.