Celebrex News
Study cites rare risk in use of bone drug UBC research cites potential harm for post-menopausal women with osteoarthritis
-Vancouver Sun
01/16/2008 - Drugs used mainly to prevent bone fractures or treat osteoarthritis, often in postmenopausal women, may cause bone tissue to crumble and die in rare situations, according to a B.C.-led study.
The research on bisphosphonates was published online Tuesday in the Journal of Rheumatology. The drug classification includes brands such as Fosamax, Alendronate, Actonel, and Didrocal.
"The results of our study demonstrate that bisphosphonate use is associated with an increased risk of AON [aseptic osteonecrosis or bone necrosis], a relatively rare but potentially serious adverse event, that was not previously reported in randomized trials," states the study by researchers at the University of B.C. and McGill University.
Bone death (necrosis) is painful and is caused by a compromised blood supply to bones. It most often affects hips, knees and shoulders and may lead to bone graft or joint replacement surgery.
There were nearly eight million prescriptions for various bisphosphonates dispensed by Canadian physicians last year (700,000 in B.C.), according to IMS Health.
The drugs are sometimes prescribed to cancer patients to prevent bone loss associated with cancer or cancer treatment such as radiation.
The study said the condition may be more prevalent in patients with malignancies or a history of cancer.
Last week, the U.S. Food and Drug Administration issued an alert about bisphosphonates. It said it was "highlighting the possibility of severe and sometimes incapacitating bone, joint and/or muscle pain in patients taking bisphosphonates."
When patients complain about such pain, doctors should consider whether the use of such drugs might be responsible, the agency advised.
In the study published Tuesday, AON was detected in 196 patients, out of a total of 87,837 Quebec patients whose health records were reviewed.
Of the 196 with bone necrosis, 40 were bisphosphonate users.
The subjects in the study were individuals who had been hospitalized for other reasons from 1996 to 2003.
The risk of being diagnosed with AON was 2.87 times greater among those who had ever used bisphosphonates, compared with non-users.
"The condition is diagnosed by either X-ray or MRI and is characterized by very sharp, incapacitating pain," said lead researcher Mahyar Etminen, whose co-researchers were Dr. Kevin Aminzadeh, Ian Matthew (UBC) and Dr. James Brophy (McGill and University of Montreal).
Etminen, a researcher with the Centre for Clinical Epidemiology and Evaluation at UBC and at the Vancouver Coastal Health Research Institute, said the theory is the bisphosphonates disrupt blood supply to the bone, which starts the necrotic process.
Healthy bone cells are continually being broken down and reformed, with minerals and other components reabsorbed by cells called osteoclasts and replaced by other cells to form new bone.
Bisphosphonates suppress the activity of osteoclasts to slow down the breakdown of bone and preserve bone density and strength, says the Canadian Medical Association book Prescription and Over the Counter Drugs for Canadians, published by Reader's Digest.
The researchers say that since bisphosphonates are potent inhibitors of bone turnover, "they gradually interfere with bone metabolism, thereby disrupting the biomechanical integrity of the bone which in turn makes the bone more susceptible to micro-damage, especially in the presence of triggers such as infection or trauma."
Dr. John Esdaile, head of rheumatology at UBC and scientific director of the Arthritis Research Centre of Canada, said in an interview that doctors were already aware of an association between intravenous bisphosphonates and bone loss in the jaw, another rare but potential side effect of the drugs.
"One always hopes when prescribing drugs that the effects will be positive but nothing is ever 100 per cent positive. Because of this research, doctors and their patients have to assess whether the drug is really needed and then weigh the risks and benefits," Esdaile said.
Although most cases of osteonecrosis of the jaw related to Fosamax side effects have occurred after dental work several cases have been reported to occur without any prior dental work. If you are currently taking Fosamax you may be at risk of developing osteonecrosis. If you have been injured by Fosamax side effects you may be entitled to compensation. For more information about your legal rights contact the Fosamax Attorneys of Ennis & Ennis, P.A. today.
