The Food and Drug Administration on Wednesday warned that Merck’s popular osteoporosis drug Fosamax and other similar drugs might increase the risk of developing a jaw infection. The disease is known as osteonecrosis of the jaw (ONJ) and is characterized by pain, soft-tissue swelling, infection, loose teeth and exposed bone.

 

The FDA warning is based on a study by Dr. Parish Sedghizadeh, an assistant professor of clinical dentistry at the University of Southern California School of Dentistry in Los Angeles who said his clinic is seeing one to four new cases a week, compared to one a year in the past.

 

For the study, Sedghizadeh and colleagues analyzed their records and identified 208 patients who took Fosamax, 66 of whom had teeth extracted. Nine of them developed ONJ – four at the site of the extraction and five after denture-related ulceration. None of the patients who did not take Fosamax who had tooth extraction developed ONJ.

 

As a possible explanation for the findings, Sedghizadeh speculated that the drugs may make it easier for bacteria to adhere to bone that is exposed after a tooth extraction.

 

The study also found that people who developed ONJ had other factors, including chemotherapy, type 2 diabetes, high blood pressure, high cholesterol and steroid therapy. Some of these conditions also contribute to the development of ONJ.

 

In the past, Fosamax and other drugs belonging to the class of bisphosphonates were associated with other problems, including an increased risk of atrial fibrillation, unusual fractures of the thighbone and inflammatory eye disease.

                               

In response to the findings of the study, Merck issued a statement saying the new study “has material methodological flaws and scientific limitations, making it unreliable as a source for valid scientific conclusions regarding the prevalence of ONJ in patients taking alendronate.”