Which of the following is a bisphosphonate used in Paget's disease management?

• A. Methotrexate
• B. Calcitriol
• C. Alendronate
• D. Infliximab

Answer: (C)

Paget disease is driven by excessive osteoclast activity leading to high bone turnover, so the treatment goal is to suppress osteoclast-mediated bone resorption. Bisphosphonates do this by binding to bone and promoting osteoclast apoptosis, which lowers bone turnover and often relieves bone pain and normalizes activity on labs and imaging. Alendronate is a nitrogen-containing bisphosphonate commonly used for Paget disease; it directly inhibits osteoclasts and has proven efficacy in reducing disease activity. The other options don’t target the underlying excessive bone resorption: methotrexate is a disease-modifying drug for inflammatory arthritis, calcitriol is active vitamin D used for mineral metabolism issues, and infliximab is a TNF inhibitor for autoimmune inflammatory conditions. Therefore, alendronate is the appropriate choice.