Fosamax belongs to a drug class known as bisphosphonates. Novartis's Aredia and Zometa injections are the two intravenous versions used in chemotherapy, and Merck's Fosamax and Procter and Gamble's Actonel are the most commonly used oral versions of the drugs.
Bisphosphonate in tablet form is commonly marketed to prevent and treat osteoporosis in post-menopausal women. Stronger forms are used to manage advanced cancers that have metastasized to the bone. For cancer therapy, the drugs are given intravenously, and usually for long periods of time.
For many years, estrogen therapy was used to prevent osteoporosis, until 2002, when a study by Women's Health Initiative said that estrogen posed more risks than benefits. When the study revealed that hormone therapy carried slight, but measurable, heart and breast cancer risks, prescriptions for bisphosphonates shot up 32%, according to IMS Health, which monitors pharmaceutical trends.
In a 2004 letter published in the Annals of Internal Medicine, researcher Susan Ott, MD, of the University of Washington wrote: "Many people believe that these drugs are 'bone builders,' but the evidence shows they are actually bone hardeners."
In a December 13, 2004, press release, doctors at Long Island Jewish (LIJ) Medical Center announced that they had discovered a link between a common chemotherapy drug and a serious bone disease called osteonecrosis of the jaw (ONJ).
The discovery, published in the Journal of Oral and Maxillofacial Surgeons, prompted both the FDA and Novartis to issue warnings to physicians and dentists about the risk for the potential adverse effect.
According to LIJ, "ONJ is a condition in which the bone tissue in the jaw fails to heal after minor trauma such as a tooth extraction, causing the bone to be exposed." The exposure, the doctors said, can eventually lead to infection and fracture and may require long-term antibiotic therapy or surgery to remove the dying bone tissue.
The chief of the Division of Oral and Maxillofacial Surgery at LIJ, Salvatore Ruggiero, DMD, MD, said they conducted the study after they noticed a cluster of cancer patients with necrotic lesions in the jaw, a condition they previously saw, in only one or 2 patients a year.
In conducting a review of the patients' charts, the doctors found that the 63 patients, diagnosed with ONJ over a 3-year period, shared one commonality, they all had received long-term bisphosphonate therapy.
Of the 63 patients diagnosed between February 2001 and November 2003, fifty-six were cancer patients who had received infusions of bisphosphonates for at least a year, and seven other patients had been receiving long-term oral therapy for osteoporosis.
"The patients developed ONJ after normal bone trauma," the press release said, "such as a tooth extraction, while receiving bisphosphonate therapy." Rather than healing, the bone began to die, and a majority of the patients required surgery to remove the diseased bone.
Another study quoted on April 4, 2006, by United Press International, found more than 2,400 patients who were taking the injected form of bisphosphonate had suffered bone damage to their jaws since 2001.
In addition to the 2,400 patients who were taking the injected form, the study found 120 patients taking the oral form of the drug who had been stricken with such incapacitating bone, joint, or muscle pain that some became bedridden and others required walkers, crutches or wheelchairs.
While the number may seem small when compared to the estimated 39 million oral prescriptions written in 2005, health experts told The Los Angeles Times that the problems may show a trend.
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