326 Obstetrics and Gynecology Board Review •••
❍ What therapies are currently available to treat osteoporosis?
Alendronate, risedronate, and ibandronate, which are bisphosphonates.
Raloxifene, a SERM.
Calcitonin nasal spray.
These are all antiresorptive agents—less bone resorbed by osteoclasts.
Another medication is teriparatide, a form of parathyroid hormone (PTH)—functions as an anabolic agent.
❍ What therapy is presently used only to prevent osteoporosis?
Estrogen-progestin therapy.
❍ In the WHI trial, what effect did estrogen plus progestin have on fracture risk?
There was a reduction in fractures of the spine and hip in patients who took estrogen plus progestin compared
with placebo.
❍ Is it necessary to supplement an osteoporosis therapy drug with calcium and vitamin D to obtain maximal
fracture protection?
Yes.
❍ How important is it for a patient at risk of osteoporosis to exercise, specifically walking and upper body
strengthening?
Extremely important. This reduces the risk of falling and thus reduces the risk of fracture.
❍ Is long-term steroid use a risk factor for osteoporosis?
Yes.
❍ How soon after starting steroids does one see significant bone loss?
3 months.
❍ What percentage of patients taking prednisone 7.5 mg or greater develop an osteoporotic fracture?
50.
❍ Can lower doses of steroids also increase risk of fracture?
Yes.
❍ Does age or gender impact fracture risk if a person is on steroids?
No.
❍ How do steroids affect bone?
They cause a toxic effect on osteoblasts, which shortens their lifespan. Calcium absorption is blocked through the
intestine. Calcium is also lost by the kidney, decreasing serum calcium. This causes PTH to be secreted, thereby
increasing bone resorption.