There are currently tens of millions of Americans taking osteoporosis drugs such as Fosamax , however few have reported any warnings from their doctors about the potential side effects of developing esophageal cancer or jaw necrosis.

A recent report from the latest issue of New England Journal of Medicine, written by Diane Wysowski, an official from the US Food and Drug Administration, reveals a total of 23 reports of esophageal cancer linked to the drug Fosamax. The reports had been sent to the FDA between October 1995 and May 2008. Eight of the patients from these reports have died so far.

In a statement by the FDA, other osteoporosis drugs were annulled from accusations as “no similar US reports for other oral bisphosphonates were retrieved from the FDA’s database for adverse-event reporting.” Such other drugs include Boniva, Actonel or Didronel, which Wysowski herself would not rule out linkages with esophageal cancer.

In Wysowski’s article, she urges physicians to avoid prescribing oral bisphosphonates, especially to patients with Barrett’s esophagus, a condition that is often a precursor to esophageal cancer.

Although in Wysowski’s article, she admits that a significant study has not been conducted towards proving that taking oral bisphosphonates will cause esophageal cancer, she notes that “use of oral bisphosphonates has been linked to inflammation of the esophagus, also called esophagitis, primarily in patients who have not used them according to directions.” Such irritation is said to be the kind of esophageal damage, which may lead to cancer later on.

Over at the University of Southern California, School of Dentistry, results have now been released for another study, which has linked oral bisphosphonates to increased jaw necrosis. This study, published in the January issue of the Journal of the American Dental Association (JADA), stresses that even short-term use of common oral osteoporosis drugs will leave the jaw vulnerable to necrosis.

Principal investigator, Parish Sedghizedeh, assistant professor of clinical dentistry from the USC School of Dentistry, notes that previous statements have ruled oral bisphosphonates and the risk of osteonecrosis of the jaw as “negligible.” Yet from Sedghizadeh’s study, he noted, “four percent is not negligible.”

The study involved 208 healthy School of Dentistry patients who had been referred to their clinics without bias, and were either taking or have taken Fosamax for any length of time. 9 of those patients developed osteonecrosis of the jaw.

One participant was surprised at these results, and commented that throughout her three-year treatment with the drug, her own doctor never told her of these risks.

The danger lies in the fact that the drug has a 10-year half life in bone tissue. Thus, even with short-term usage, there remains long-term risks.

Further complications may occur for patients who require teeth extractions. “The infection is a biofilm bacterial process, meaning that the bacteria infecting the mouth and jaw tissues reside within a slimy matrix that protects the bacteria from many conventional antibiotic treatments, and bisphosphonate use may make the infection more aggressive in adhering to the jaw,” said Sedghizadeh.

Thus when procedures directly expose the jaw, such as tooth extractions or other oral surgery, the risk of bacterial infections are greater. One patient took one year to heal from her tooth extraction, and had a rigorous oral hygiene regimen monitored by the USC dentists to ensure her healing.

“We’re getting two or three new patients a week that have bisphosphonate-related ONJ,” said Sedghizadeh, who hopes that further research will be conducted to confirm his findings of this link between Fosamax and other oral bisphosphonate drugs and jaw necrosis.