14 December 2007

National Prescribing Service Limited (NPS) has today published a fact sheet to inform health professionals about a rare but possible side effect of bisphosphonates – Osteonecrosis of the Jaw (ONJ), which is the breakdown of bone in the jaw.

NPS advises that there is no need for people to stop taking their osteoporosis medicines as this is a rare adverse effect.

It is more common in people using high dose intravenous bisphosphonates for malignancy – where the estimated risk is around 0.88%–1.15%.

The estimated incidence in people taking bisphosphonates for the treatment of osteoporosis is lower, at around 0.01%–0.04%. However the risk increases to 1% for people who have a dental extraction while on bisphosphonates.

Once it does occur, ONJ is difficult to treat and may not resolve. According to NPS CEO, Dr Lynn  Weekes, it is essential for doctors to assess the patient’s risk, and refer them for a dental check-up  and any necessary dental work before starting a bisphosphonate. Doing so may help to minimise the likelihood of this adverse effect.

People taking these drugs do need to be aware of the signs and symptoms of ONJ which can include exposed bone, severe jaw pain, numbness, loose teeth, oral odour, infection, impaired healing and denture sore spots. Patients should be advised to notify their doctor of any dental problems as soon as possible.

“There is no reason for people being treated for osteoporosis to stop taking bisphosphonates because of this adverse effect, as the risk of osteonecrosis is probably much less than the risk of a fracture in someone with osteoporosis” Dr Weekes explained.

“It’s important that people already receiving a bisphosphonate do not have dental surgery until their risk of osteonecrosis of the jaw has been assessed.”

“People should not stop taking their osteoporosis medicines because this is a rare adverse effect.  Anybody concerned about the possible side effects of their medicine should talk to their doctor” concluded Dr Weekes

Avoiding dental surgery during bisphosphonate therapy is especially important for people at risk of  osteonecrosis of the jaw, such as those receiving large intravenous doses for malignancy. Other risk factors to consider include advanced age, long-term therapy, immunosuppression and co-morbidities I.

For the cost of a local call TAIS line provides confidential health professional access to independent  drug and therapeutics information. Telephone: 1300 138 677 (local call charge)

For the full text of the fact sheet visit www.nps.org.au/healthpro

For more information see:NPS News 53: See Preventing osteonecrosis of the jaw (page 3)

NPS Radar: Alendronate

ENDS

National Prescribing Service Limited (NPS) is an independent, non-profit organisation for Quality Use of Medicines funded by the Australian Government Department of Health and Ageing.