Which medication class is commonly used to treat osteoporosis?

• A. Calcium carbonate supplements.
• B. Selective estrogen receptor modulators.
• C. Calcitonin.
• D. Bisphosphonates.

Answer: (D)

Reducing bone resorption to prevent fractures is the central idea in treating osteoporosis. Bisphosphonates are the most commonly used and most effective class for this purpose because they strongly inhibit osteoclast-mediated bone resorption. They bind to bone surfaces and, when osteoclasts resorb bone, they release the drug, which disrupts the mevalonate pathway inside osteoclasts, leading to osteoclast apoptosis and a sustained decrease in bone turnover. Over time this increases bone mineral density and lowers the risk of vertebral, non-vertebral, and hip fractures. They’re widely used as first-line therapy and come in oral forms (weekly or monthly) or an IV infusion (annual or biannual), with dosing tailored to adherence and patient risk.

Calcium carbonate supplements support bone health by providing calcium, but they don’t directly suppress bone resorption or reduce fracture risk as effectively when used alone. Selective estrogen receptor modulators can reduce vertebral fracture risk but carry risks such as thromboembolism and don’t protect as well against hip fractures. Calcitonin is less potent for fracture prevention and is used less routinely today. Thus, bisphosphonates best fit the goal of actively reducing fracture risk in osteoporosis.