Switching Osteoporosis Medications

Content provided by the Faculty of the Harvard Medical School

Switching Osteoporosis Medications

Question:

I've been taking Fosamax for four years. Is there any problem if I switch now to Actonel?

Answer:

Alendronate (Fosamax) and risedronate (Actonel) are medications most commonly taken to prevent or treat osteoporosis. They are members of a family of medicines called bisphosphonates that can increase bone density and reduce the risk of fracture.

There's no specific reason to avoid Actonel if you've been taking Fosamax in the past. However, there are a number of important factors to consider when deciding whether to continue or switch medicines for osteoporosis:

The reason the medication was prescribed in the first place

For example, if a bone density test revealed osteoporosis, treatment with a bisphosphonate is usually recommended. However, if bone density is only mildly low (a condition called osteopenia), treatment with a bisphosphonate may not be necessary.

The trend of bone density test results

If bone density is falling over time, a bisphosphonate medication may make sense even before osteoporosis develops.

Prior fractures related to low bone density

When fractures have occurred after minimal or no impact and no explanation is evident other than low bone density, a bisphosphonate medication is usually a good idea.

Risk factors

A person with multiple risk factors for osteoporosis (such as advanced age, family history, or corticosteroid use) is a better candidate for treatment than someone with no risk factors.

Response to treatment

If Fosamax therapy does not improve bone density, switching to Actonel may be worth a try. However, these two medications are, on average, quite similar in their capacity to increase bone density and reduce fracture risk.

Side effects

For example, Fosamax or Actonel may occasionally cause intolerable heartburn. This side effect is similarly likely with either medicine. Switching to an injectable bisphosphonate (such as zoledronic acid) is one way to get around this side effect.

Cost

Depending on such factors as insurance coverage, dosage, and where you live, the cost of one bisphosphonate may be much more expensive than another.

Options other than bisphosphonate medications

Routine recommendations to improve and maintain bone strength include weight-bearing exercise and adequate calcium and vitamin D intake. In certain circumstances, other medications, such as raloxifene (Evista) or teriparatide (Forteo) may be a better option than switching between bisphosphonates.

Duration of therapy

There is evidence that after five years of treatment with alendronate, many people can safely stop treatment (at least for several years).

Review these issues with your doctor. There may be good reasons to switch from Fosamax to Actonel. However, these two medicines are fairly similar in their action, benefits and risks, and there are other options to consider.

Robert Shmerling, M.D., is associate physician and clinical chief of rheumatology at Beth Israel Deaconess Medical Center and an associate professor in medicine at Harvard Medical School. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program and has been a practicing rheumatologist for over 25 years.

Last updated:	July 20, 2009