Which of the following is NOT a common adverse effect of bisphosphonates?

• A. GI irritation and esophagitis
• B. Osteonecrosis of the jaw
• C. Hyperglycemia
• D. Atypical femur fractures

Answer: (C)

Bisphosphonates work by inhibiting osteoclast activity, which lowers bone turnover and helps strengthen bone in osteoporosis. This mechanism is linked to several well-recognized adverse effects. Oral formulations often cause GI irritation and esophagitis because the pill passes through and can irritate the esophageal lining if not taken with water or if the patient doesn’t stay upright. Osteonecrosis of the jaw is a serious but less common risk, especially with IV therapy or after dental procedures in those with prolonged exposure to these drugs. Long-term use can lead to atypical femur fractures due to overly suppressed bone remodeling and accumulation of microdamage.

Hyperglycemia is not a typical adverse effect of bisphosphonates, since these drugs don’t directly affect glucose metabolism or pancreatic function. If elevated blood glucose occurs, it’s more likely related to other conditions or medications rather than the bisphosphonate itself.