I selected a few excerpts from a patient information review in the New York Times:
What is osteoporosis
Osteoporosis is defined as having a bone mineral density T score of minus 2.5 or lower. Lesser degrees of bone loss, known as osteopenia, may not benefit from drug therapy.
The first drug licensed to counter osteoporosis, Fosamax, is now available generically as alendronate, which can be taken once a day or, at a higher dose, once a week. A reluctance on the part of many patients to adhere to a daily or weekly regimen led to the development of Boniva (ibandronate), administered by an intravenous injection every three months. To further simplify the frequency of administration, Reclast (zoledronic acid) was developed as a once-a-year intravenous treatment.
Actonel, alendronate and Boniva have been shown in three-year studies of postmenopausal women to reduce vertebral fractures by 41-50%, and less for other kinds of fractures.
A three-year study of Reclast found it to be somewhat more effective, with a 70 percent reduction in vertebral fractures, 41 percent in hip fractures and 25 percent in other fractures in postmenopausal women with osteoporosis.
Side Effects of Bisphosphonates
In a large study of Reclast, there was also a worrisome increase in atrial fibrillation — an irregular heart rhythm — not known to occur with other bisphosphonates.
Low-trauma fracture with a delay in healing or complete failure may occur after many years on bisphosphonates.
These side effects have prompted a warning that after five years on bisphosphonates, people should take a break from the drugs for at least a year.
Evista (raloxifene) has an added advantage of reducing the risk of breast cancer, but the disadvantage of increasing the risk of deep vein blood clots.
Somewhat less effective at reducing vertebral fractures is calcitonin, a naturally occurring hormone sold as Fortical and Miacalcin.
Finally, there is the bone-building drug Forteo (teriparatide), which must be self-injected once a day. This human parathyroid hormone can reduce vertebral fractures by 65 percent and other fractures by 53 percent within 18 months in patients with osteoporosis.
Under study is an entirely new bone drug, denosumab, a human monoclonal antibody. The drug inhibits a receptor that activates cells called osteoclasts that break down bone. In a large three-year study, denosumab, given by injection every six months to postmenopausal women with osteoporosis, reduced vertebral fractures by 68 percent and hip fractures by 40 percent.
Options for Bone Loss, but No Magic Pill. NYT, January 4, 2010.
Denosumab is a monoclonal antibody that reduces fractures in osteoporosis
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