Jaw osteonecrosis and bisphosphonates for osteoporosis

May 16, 2006

May 16, 2006

Philadelphia, PA - A review of jaw osteonecrosis as a recently described adverse effect of bisphosphonate therapy in the May 16, 2006 issue of the Annals of Internal Medicine concludes that most cases have developed in cancer patients being treated with intravenous products but adds that cases have also been reported in patients taking oral bisphosphonates for osteoporosis [ 1 ].

The concern is that with more women aging and taking bisphosphonates for longer periods of time, more cases of osteonecrosis may develop even in patients receiving alendronate or ibandronate therapy.

Written by Dr Sook-Bin Woo (Brigham and Women's Hospital, Boston, MA) and colleagues from the University of Iowa and Ohio State University, the article is a position paper of the American Academy of Oral and Maxillofacial Pathology. The authors note that an increasing body of literature about this side effect has built up over the past two years, and in their paper they review 368 cases. They point out that 94% of patients with this adverse effect were taking intravenous bisphosphonate products primarily pamidronate (Aredia, Novartis) and zoledronic acid (Zometa, Novartis) and 83% of these patients had multiple myeloma or metastatic breast cancer.

Only 4% of the cases reviewed (15 patients) were being treated for osteoporosis. Of these, 13 patients had been taking alendronate (Fosamax, Merck & Co); one patient took alendronate as well as intravenous zoledronic acid and one patient took risedronate (Actonel, Procter & Gamble). The authors point out that one patient had been taking alendronate for only two years when the jaw osteonecrosis occurred and comment: "The concern is that with more women aging and taking bisphosphonates for longer periods of time, more cases of osteonecrosis may develop even in patients receiving alendronate or ibandronate therapy." Ibandronate (Boniva, Roche), recently approved for use in osteoporosis, is a potent nitrogen-containing bisphosphonate, like alendronate, risedronate, zoledronic acid, and pamidronate. However, while jaw osteonecrosis has been reported with these other drugs, it hasn't as yet been reported with ibandronate, and the risks associated with this product are unknown, the authors add.

"The degree of risk for osteonecrosis in patients taking oral bisphosphonates, such as alendronate, for osteoporosis is uncertain and warrants careful monitoring," the review concludes. As previously reported by rheumawire , in the US there is currently ongoing litigation over jaw osteonecrosis occurring as a side effect of bisphosphonate therapy, and a class action has been filed against Merck for alendronate.


What to look out for

The degree of risk for osteonecrosis in patients taking oral bisphosphonates, such as alendronate, for osteoporosis is uncertain and warrants careful monitoring.

The authors also describe what to look out for with this adverse effect. Clinically, intraoral lesions appear as areas of exposed yellow-white, hard bone with smooth or ragged borders, they write. Sinus tracts may be seen either in the mouth or around it (one photographed case shows a sinus tract opening out under the chin). There may also be painful ulcers in soft tissue that impinges on the ragged bony margins.

More than half of all cases (60%) occur after dentoalveolar surgery, such as tooth extraction, to treat infection, and the remaining 40% of casers are probably related to infection, denture trauma, or other physical trauma. Preventive strategies include removing all sites of active and potential jaw infection before starting bisphosphonate therapy to minimize the need for future oral surgery. Similar protocols have already been established for patients preparing for allogenic stem-cell transplantation and those about to receive radiation to the head and neck, the authors point out.

Source

  1. Woo SB, Helstein JW, Kalmar JR. Systematic review: bisphosphonates and osteonecrosis of the jaw. Ann Int Med 2006; 144:753-761.

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