A review of the study published in the Journal of Orthopaedic Trauma found that 19 times as many patients who were taking Fosamax experienced stress fractures in the bones of the leg compared with other patients. Researchers concluded that Fosamax could prevent bones from being able to properly heal, leading to the increased risk of fractures.

“We believe that the long term use of these drugs may suppress the ability of bones to heal in some patients,” said Dr. Dean Lorich, one of the lead researchers with the study. “As a consequence, patients with routine stress fractures are unable to properly heal, and minor damage can worsen until serious fractures occur.”

In addition to an increased risk of fractures, the potential Fosamax side effects include a condition known as osteonecrosis of the jaw. Patients who suffer from this condition may experience a rotting away of the jawbone tissue due to the inability of the bones to heals.