What are the reasons that would stop bone medications from working in relation to halting rapid osteoporosis?

Absorption: The most common cause for bone antiresorptive medications to not work is that they are not being taken correctly, and not being absorbed into the blood stream. This is especially true for bisphosphonates. One also needs to look for a secondary cause of osteoporosis such as hyperparathyroidism, hyperthyroid, steroid effects, other meds.