The Federal Drug Administration (FDA) has reported that Fosamax (alendronate), a bisphosphonate (BP) used to treat osteoporosis, has been linked to esophageal cancer.

Another study reports that BPs increase the risk of osteonecrosis of the jaw (ONJ), a disease resulting from the loss or decrease of blood supply to the bone.

BPs are a class of drugs that reduce the risk of bone fracture and increase bone mass by slowing or stopping the breaking down of bone by osteoclasts.

In multiple myeloma patients, BPs reduce pain, breaks in the vertebrae, and hypercalcemia (increased levels of calcium in the blood). It is recommended that all myeloma patients take a BP if they present no contraindications.

While Fosamax is not typically used to treat multiple myeloma patients, other BPs—Aredia ^[1] (pamidronate) and Zometa ^[2] (zoledronic acid)—are. The findings suggest that similar medical complications involving these BPs should also be investigated.

Between October 1995 and May 2008, the FDA received 23 reports of esophageal tumors (tumors of the tube carrying food to the stomach) in patients taking Fosamax. All of these patients suffered from osteoporosis (low bone density). Eight of the 23 patients died. The average time between start of the drug and cancer development was just over two years.

Similarly, in Europe, six out of 21 patients who developed tumors have died.

While BPs have been known to increase the risk of esophagitis, an inflammation of the esophageal lining, their connection to esophageal cancer has not been well-defined.

Another study has reported that BPs are linked to ONJ, a condition characterized by pain, soft-tissue swelling, infection, loose teeth, and exposed bone.

Based on the University of Southern California School of Dentistry’s electronic database, nine of the 208 patients taking Fosamax developed ONJ. All nine patients had undergone a dental procedure, usually tooth extraction. Researchers speculate that BPs may make it easier for bacteria to stick to exposed bone that results from dental procedures.

Other problems that are associated with BPs are increased risk of atrial fibrillation (an abnormal heart rhythm), unusual fractures of the thigh bone, and inflammatory eye disease.

The findings may have important therapeutic and preventative implications. Further research will shed more light on complications that stem from the use of BPs.

The original articles in the New England Journal of Medicine ^[3] and the Journal of the American Dental Association ^[4] can be read by journal subscribers. Non-subscribers can find more information about BPs and esophageal cancer from Reuters ^[5] or NewsInferno ^[6] and about BPs and ONJ in HealthDay ^[7].