Osteoporosis is a disease causing the bones to become thin, weak, and fracture easily. According to the National Osteoporosis Foundation, ten million Americans have the condition, and nearly 34 million more are at risk for developing it because they have low bone mass. The condition is often called the "silent disease" because many people don't know they have it until they experience an unexpected fracture.
Osteoporosis is four times more common in women than in men. Some other risk factors include having a small or thin body frame, being 50 or older, family history of osteoporosis, (in women) lack of menstrual periods or being postmenopausal, inadequate calcium intake, sedentary lifestyle, smoking cigarettes, excessive consumption of alcohol, and use of certain medications. Osteoporosis is responsible for roughly 1.5 million fractures/year. The most common sites of fracture are the hips, spine and wrist. Hip fractures are potentially devastating – about 24 percent of patients over 50 die within a year of the fracture and another 25 percent require long-term nursing care.
Medications for Osteoporosis
There is no cure for osteoporosis, but several treatments are available. Patients should get the recommended allowance of calcium and vitamin D, participate in a regular weight-bearing exercise program, and avoid use of cigarettes or excessive amounts of alcohol. For postmenopausal women, estrogen replacement therapy may reduce bone loss and increase bone density in the spine and hip. Raloxifene (Evista®), a drug in a class known as selective estrogen receptor modulators, may also reduce bone loss and increase bone mass. Calcitonin (Miacalcin®) is a naturally-occurring hormone which can slow bone loss and increase bone density in the spine.
So far, the only medications which have been proven to reduce the risk of hip fractures are the oral biphosphonates – alendronate (Fosamax®) and Risedronate (Actonel®). However the drugs can have side effects, such as abdominal pain, esophageal inflammation, nausea, and heartburn. They must be taken on an empty stomach. In addition, patients need to stay in an upright position for at least half an hour after taking the medication.
Researchers are testing various other medications for osteoporosis. Pamidronate is an intravenous biphosphonate currently approved for cancer patients experiencing hypercalcemia. Some investigators are testing it for postmenopausal osteoporosis. So far, there is little data to support off-label use of the drug. In addition, an infusion of pamidronate takes several hours.
Another intravenous biphosphonate is zoledronic acid (Zometa). It's also approved for cancer patients with hypercalcemia. But unlike pamidronate, zoledronic acid can be given in just a few minutes. In a recent study published in the New England Journal of Medicine, doctors found the drug increased bone density in the hip and spine and appeared to reduce bone turnover. The most striking finding – the drug appeared to remain effective for a year after a single 4-mg dose. Side effects were reportedly mild and included nausea and mild aches and pain, and were generally limited to the first dose.
Zoledronic acid is the same drug found in the oral biphosphonates. However, an intravenous, single dose form of the drug poses many advantages over the oral medication. Patients may be more likely to adhere to the medication since it doesn't cause gastrointestinal side effects. In addition, a once-yearly dose may be more convenient than remembering to take daily doses.
Researchers have started a large multi-center study to determine the long-term effectiveness of Zoledronic acid. Investigators will follow 3,000 patients with osteoporotic hip fractures and determine if the intravenous medication will prevent future hip fractures. For more information or referral to a study site, call 410-332-9767.
For study information or referral to other study sites, call (410) 332-9767.
For information on osteoporosis: American Society for Bone and Mineral Research, 2025 "M" Street, NW, Suite 800, Washington, DC 20036, www.asbmr.org
National Institutes of Health, Osteoporosis and Related Bone Diseases~National Resource Center, 1232 22nd Street, NW, Washington, DC 20037, www.osteo.org , (800) 624-BONE