SPECIALISTS IN the Republic have played down fears that a drug commonly used in the treatment of osteoporosis (thinning of the bone) can cause severe jaw problems.
In an editorial in the current issue of the Irish Medical Journal, consultant rheumatologists in Galway and Dublin say the risk of osteonecrosis of the jaw as a result of taking bisphosphonates is "very small".
The Irish Medicines Board (IMB) issued a warning last January about the drug. "Osteonecrosis of the jaw continues to be reported as a suspected adverse drug reaction associated with bisphosphonates and the number of reports appear to be increasing, particularly for the most potent bisphosphonates," it said in a statement.
Osteonecrosis is a rare but extremely painful condition in which part of the jaw bone dies. But several hundred cases of bisphosphonate with osteonecrosis of the jaw (BONJ) have been reported in medical literature since 2003. Some 95 per cent of cases involved the intravenous use of bisphosphonates given at much higher doses in bone cancer patients.
Although the condition has been intensively studied since it first came to light in 2003- 2004, the reason it happens has not yet been identified. Nor have doctors and dentists been able to unravel the disease process linking the drug with the destruction of bone.
Dr John Carey, consultant rheumatologist at University Hospital Galway (UHG) and his colleagues say: "The weight of evidence from randomised control trials, and large observational studies with appropriate control groups does not support an increased risk of osteonecrosis of the jaw in persons treated with bisphosphonates for osteoporosis. This implies that there is either no increased risk, or if there is, it is likely very small."
Referring to concerns about BONJ in literature and the media, the authors state: "It is incumbent on societies and regulatory authorities to take care when issuing warnings on prescribing information. In clinical practice, patients have stopped taking bisphosphonate therapy or are worried about continuing therapy.
"There is a burden of uncertainty among patients and healthcare professionals about an entire class of drugs which are of clear proven benefit for a major public health condition (osteoporosis)."
The specialists challenge the advice of both regulatory agencies and professional associations. They say the addition of osteonecrosis of the jaw to the precautions list of the prescribing information for bisphosphonates is not supported by data from clinical trials. And they say the American Dental Association is wrong when it recommends a dental evaluation for patients before they start oral bisphosphonate treatment.
Dr Carey and his colleagues say doctors should reassure patients that the risk is small. "As with everything we do, risk should be put in perspective: the risk of developing the condition would seem to be much less than the lifetime risk of dying on a plane (1:5,000) . . ."
The brand names of bisphosphonates available on the market here include: Fosamax, Osteomel, Bonefos, Didronel, Bonviva, Actonel and Aclasta.