Which agent for osteoporosis should be limited to no more than 2 years?

The agent that should be limited to no more than 2 years of use is teriparatide. Teriparatide is a recombinant form of parathyroid hormone, which is used for the treatment of osteoporosis, particularly in individuals at high risk for fracture. It works by stimulating bone formation and increasing bone density.

The reason for limiting teriparatide therapy to 2 years is primarily due to safety concerns. Clinical studies have indicated that long-term use of teriparatide may be associated with an increased risk of osteosarcoma, a type of bone cancer. Therefore, to mitigate this risk, the treatment duration is restricted. After a maximum of 2 years of teriparatide therapy, patients typically transition to other osteoporosis medications that maintain bone density without the same safety concerns that limit the use of teriparatide.

In contrast, other agents mentioned, such as calcitonin, denosumab, and zoledronic acid, do not have the same duration limitations based on safety profiles or risk of malignancy. Each of these has its own recommended treatment duration based on their mechanisms of action and the clinical condition they are addressing, making teriparatide unique in requiring a defined limit on its use duration.