Osteonecrosis of the jaw occurs when the jawbone is exposed and begins to starve from a lack of blood. Although the risk for this adverse event is low for all bisphosphonates, it is mostly reported with Reclast and pamidronate, an older bisphosphonate that’s given intravenously. Doctors sometimes use these therapies in very potent doses to prevent fractures and bone loss associated with cancer or cancer treatments, according to American Bone Health. There are ways to minimize the risk of jaw osteonecrosis, including getting a dental exam before starting therapy on a bisphosphonate, practicing good dental hygiene, and avoiding invasive dental procedures while taking the medication.

Atypical Femoral Fracture - Bisphosphonates can also carry a risk of atypical femoral fracture, which starts when the outer rim of the femur (thigh bone) starts to weaken. Unlike stress fractures or other bone breaks, the bone cracks from just normal activity. An aching pain in the groin or thigh can be a warning signal that this may be happening, according to American Bone Health. With no intervention, the crack continues to grow and eventually the thigh bone breaks in two.

Drug Holiday to Minimize Risks - The longer a person takes a bisphosphonate, the greater the risk for both jaw necrosis and atypical femoral fracture, especially after three years. In an effort to minimize the risk as much as a possible, a drug holiday is recommended. A drug holiday is a temporary stop of a medication (in this case, bisphosphonate) in an effort to prevent the potential side effects. A study published in December 2018 in Endocrine Practice found that 15.4 percent of patients who take a break from their bisphosphonate treatment had a bone fracture. The study authors recommended that people who have a high risk of fracture be closely followed by their doctor during drug holiday.