Fosamax, Forteo - How Do You Decide Which Treatment Works After Breast Cancer?

Health Professional

Reader Question: My mom is 75 and is recovering from a fractured wrist and arm. She has been taking Fosamax for about three months. Is there any other treatment? I was wondering if she could take Forteo because she had radiation for breast cancer. It was the estrogen receptor form of cancer and not bone cancer. I read that patients who had radiation to the bones could not take Forteo.

Osteoporosis Medications

There are numerous medications for osteoporosis on the market.

Class: Bisphosphonate

Drug: Fosamax, Actonel, Boniva

Way it works: Stops removal of bone

Class: Selective estrogen receptor modulators (SERMs)

Drug: Evista (raloxifene)

Way it works: Selective Estrogen blocker

Class: Synthetic Parathyroid Hormone (PTH)

Drug: Forteo (Teriparatide)

Way it works: Adds Bone

Class: Calcitonin hormone

Drug: Miacalcin

Way it works: Stops removal of bone

  • Bisphosphonates are considered the most potent oral osteoporosis medication. They work by blocking the cells that take away bone. Fosamax was the first bisphosphonate approved for osteoporosis. It is the most well-known and is the most prescribed. It is available in a weekly dose, with additional Vitamin D, allowing one to fulfill the new National Osteoporosis Foundation guidelines of 800 IU per day. Actonel is considered as potent and is now available in a convenient two-day consecutive day dosing (two days in a row and you are finished for the month). Boniva is the newest one available and is a one time per month dose. Major side effects of this drug class are uncommon, but include stomach upset, and muscle aches.

For a more complete discussion on these agents, please see my previous blog:

  • SERMS: Evista selectively blocks the effects of estrogen on breast tissue and uterine tissue, while selectively mimicking the effects of estrogen on bone (by increasing bone mineral density). It has been shown to be effective at decreasing vertebral fractures, but not non vertebral (wrist/hip etc.) Initial results, from a large national study called STAR (Study of Tamoxifen and Raloxifene) which included nearly 20,000 postmenopausal women, showed that Evista equaled Tamoxifen, an established breast cancer reduction drug, at preventing breast cancer in postmenopausal women at increased risk of breast cancer. Side effects include hot flashes and rarely clotting in the deep veins.

  • PTH:** Forteo** is a very effective agent for osteoporosis at both vertebral and non-vertebral areas. It works by mimicking the hormone parathyroid, which is the primary regulator of calcium and phosphate metabolism in bones. Daily injections of Teriparatide stimulate new bone formation leading to increased bone mineral density. It is approved for treatment of osteoporosis in patients who are at high risk of having a fracture and is limited to 2 years of therapy. Due to cases of osteosarcomas (bone cancer) seen in their studies involving rats, there is a black box warning on this agent. It should not be used in patient who have diagnosed bone cancer or other cancers that have spread to the bones, as well as those patients who have received radiation therapy.** While the fear of cancer concerns many, over the past few years unexpected cases of cancer have not been seen. It is also important to note that the risk of fracture and death is very real in people with osteoporosis and one should weigh that carefully against any possible side effects, especially one that has not been proven.** Side effects include possible nausea, leg cramps and dizziness.

  • Calcitonin: The most common form of Calcitonin used in the market is** Miacalcin**. Calcitonin is a hormone which is naturally produced in the thyroid. It stops the cells which continuously take away bone and is available as a daily nasal spray. It has been shown to decrease vertebral fractures, although like Evista, it did not show any effect on non vertebral areas. The fracture protection this drug gives does not appear to be related to its effect on bone density, which is minimal. Side effects include possible nasal irritation, backache, bloody nose, and headaches.

It is evident from the above that a careful evaluation of the bone density, of all underlying diseases, as well as the risk factors of each individual patient must be done prior to making any decision on specific osteoporosis therapies.