Now that hormone replacement is no longer considered safe to be used long term, the bisphosphonate drug Fosamax or Alendronate is the most commonly prescribed treatment for osteoporosis. Another commonly prescribed bisphosphonate is Actonel or Risedronate. But claims that Fosamax significantly reduces fracture rates in women with low bone density do not have the evidence to support them, and concerns have been raised that because bisphosphonates suppress normal bone remodeling, using the drug for more than five years may produce an older skeleton with more crystalized bone which fractures more easily and has less tensile strength in places like the hip.
Fosamax is claimed to reduce hip fractures by 50 percent in women with low bone density and previous vertebral fracture. But the actual or absolute reduction is one percent. In real terms, 90 such women would need to be treated for three years to prevent one hip fracture in one of them. The remaining 89 would receive no benefit. It is estimated that hundreds of women aged 50 years with low bone density alone would need to be treated for more than 3 years to prevent one hip fracture in one of them.
Leading osteoporosis authority Professor Ego Seeman of the University of Melbourne, Australia, poses the question: “Should we expose huge numbers of these women [age 50 and with low bone density] to a drug, its costs, inconveniences, side-effects, when most will not sustain a fracture had no treatment been given? That is, most who take the drug will be exposed to the risk of side effects and costs and receive no benefit…This is the nature of preventive medicine; we have to treat large numbers to avert events in few. This is why the drugs we use must be safe — because most exposed do not benefit, and even a small number of adverse events can tip the balance of net benefit to net harm.”
Although a recent small study showed that bone mineral density continued to increase with up to 10 years of Fosamax use, it is not at all clear that this means a reduction in fracture. The research that answers this question has yet to be done. Increased bone mineralization has been shown to increase micro-fracturing in animal studies.
Bisphosphonates are long-acting medications. Their half-life (continuing effect in the body) is estimated to exceed 10 years. Stopping usage means that exposure to the drug continues indefinitely. As long as we do not know the long term effects of taking bisphosphonates, this is a real concern. In addition, little is known about the effect of these drugs on women of childbearing years. There are concerns that the drug could affect skeletal development of the unborn child. For this reason they are not recommended for any premenopausal woman.
Bisphosphonates can have unpleasant side effects and administration can be difficult. It is necessary to accept a strict regimen to prevent potentially serious stomach problems and to maximize absorption. Recently, a once-weekly, rather than a daily, dose of both alendronate and risedronate has been approved by the FDA. Some bisphosphonates like Pamidronate are administered by injection.
Read more in the Bisphosphonates Fact Sheet
Raloxifene
The SERM (selective estrogen receptor modulator) Raloxifene (or Evista), is marketed widely as a treatment option that shows great promise. But although there is some evidence that Raloxifene will help prevent vertebral fractures, there is no evidence that it will prevent hip fracture. It does decreases breast cancer risk in women with osteoporosis who are at low risk for breast cancer to begin with and a further study is looking at whether it will prevent breast cancer in women at high risk. SERMs can increase menopausal symptoms of hot flushes by 50 percent and increase the risk for potentially fatal deep vein thrombosis and pulmonary embolism.
Parathyroid hormone (PTH)
PTH or Forteo is different from other osteoporosis drugs in that it stimulates bone formation and may even rebuild trabecular bone, the meshed honey-comb type of bone found in the hip and in the vertebrae. PTH treatment also appears to significantly reduce fractures.
Because it is a new and very expensive drug, Forteo is only FDA approved for the treatment of osteoporosis in postmenopausal women who are at high risk for a fracture. It is also approved to increase bone mass in men with primary or hypogonadal osteoporosis who are at high risk for a fracture. Forteo has not been studied beyond 2 years and is therefore not recommended for use beyond that period of time.
The Forteo label comes with a ‘black box’ warning. As part of drug testing, Forteo was given to rats and some of then developed osteosarcoma, a bone cancer. Osteosarcoma in humans is a serious but very rare cancer. It is not yet known if humans treated with Forteo also have a higher chance of getting osteosarcoma.
The rush to provide costly and risky medical solutions for low bone density in healthy postmenopausal women is drawing attention away from the very important issues of preventing falls in the elderly, diagnosing genuine sufferers, and encouraging regular exercise and appropriate diet to maintain bone health.
Read more about osteoporosis treatments and safe and effective alternatives in The Myth of Osteoporosis.
References:
Heaney, RP. Bone mass, bone fragility, and the decision to treat. JAMA 1998:280;2119-2120
Wilkin TJ, et al. Bone densitometry is not a good predictor of hip fracture. BMJ 2001:323:795-9
Black, D.M., Cummings, S.R.et al. ‘Randomised trial of effect of alendronate on risk of fracture in women with existing vertebral fractures.’ Lancet 1996;348:1535-41
Seeman, E. ‘Treatment of asymptomatic osteopenic menopausal women.’ Medscape Ob/Gyn & Women’s Health 2002. Available at: http://www.medscape.com/viewarticle/446109?mpid=7785
Seeman, E. ibid
Bone HG, Hosking, D, Devogelaer JP, et al. Ten Years' Experience with Alendronate for Osteoporosis in Postmenopausal Women. New England Journal of Medicine. 2004. 350(12): 1189-1199.content.nejm.org/12/1189
Komatsubara S, Mori S, Mashiba T, Li J, Nonaka K, Kaji Y, Akiyama T, Miyamoto K, Cao Y, Kawanishi J, Norimatsu H. ‘Suppressed bone turnover by long-term bisphosphonate treatment accumulates microdamage but maintains intrinsic material properties in cortical bone of dog rib.’ J Bone Miner Res. 2004 Jun;19(6):999-1005.
Kaunitz, A.M. ‘Osteopenia in a Premenopausal Woman.’ Medscape Ob/Gyn/Gyn&Women’s Health 8(1),2003. Available at: http://www.medscape.com/viewarticle/447116
Mintzes, Barbara.The truth, the half truth, and nothing like the truth. Regulation of drug promotion in Canada. Tales from other drug wars. Paper from the 12th Annual Health Policy Conference. Vancouver BC. Nov 26 1999. ISBN 0-88865-240-2