Which statement best describes the risk of IV zoledronic acid compared with oral bisphosphonates?

• A. Flu-like symptoms and hypocalcemia risk
• B. No risk of adverse effects
• C. It always causes severe hypertension
• D. It is safer in all patients with no side effects

Answer: (A)

IV zoledronic acid can provoke systemic adverse effects that are less common with oral bisphosphonates. The most notable risks after an infusion are an acute-phase reaction—flu-like symptoms such as fever, fatigue, and myalgias—that can occur within 24 to 72 hours after the dose. It also carries a higher risk of hypocalcemia because the potent, rapid suppression of bone turnover can lower serum calcium, especially in patients with low vitamin D levels, inadequate dietary calcium, or impaired renal function. Oral bisphosphonates tend to cause mainly gastrointestinal side effects and are less likely to trigger these acute systemic reactions. Therefore, describing the risk as including flu-like symptoms and hypocalcemia reflects the distinct adverse-effect profile of IV zoledronic acid compared with oral options.