Is The Fact That Fosamax Has Been The Most Prescribed -- More Often Than Actonel, Aredia, Boniva, Etc. -- Blurring The Answer To This Drug-Safety Issue?
(Posted by Tom Lamb at DrugInjuryWatch.com)
In June 2012 the (then) Archives of Internal Medicine published an article "Atypical Femoral Fractures Associated With Bisphosphonate Use", which has raised the issue of whether this femur bone break is a side effect specific to Fosamax (alendronate) and, perhaps, Aredia (pamidronate) or whether it is an adverse event for all bisphosphonate drugs, i.e., class effect.
This drug-safety issue concerning Fosamax-related atypical femur fractures is discussed in the January 14, 2013 edition of the medical journal JAMA Internal Medicine (formerly Archives of Internal Medicine). From the Editor's Correspondence section, we start with "Are Bisphosphonates Associated With an Increased Risk of Atypical Femoral Fractures as a Class?", which makes the inquiry whether the authors of that June 2012 bisphosphonate femoral fracture study article failed to distinguish between the increased risk which could be attributed to the several different bisphosphonate drugs. This January 2013 letter by Michael Pazianas, MD, seems to base its inquiry on this point:
It is now well recognized that individual bisphosphonates differ in their pharmacological properties. [The authors of the June 2012 article], however, conclude that the use of bisphosphonates (as a class) is associated with an increased risk of atypical fractures, despite the fact that in Table 1 of their article, most of the listed atypical fractures occurred in [Fosamax (alendronate)] users.
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In turn, the authors of that June 2012 article -- Raphael P. H. Meier, MD; Rene Rizzoli, MD; Robin E. Peter, MD -- address this new inquiry in their piece, "Are Bisphosphonates Associated With an Increased Risk of Atypical Femoral Fractures as a Class?—Reply":
We agree that bisphosphonates differ in their pharmacological proprieties and should therefore be individually analyzed, particularly when looking at their potential adverse effects. In our study, [Fosamax (alendronate)] and [Aredia (pamidronate)] use was associated with significantly higher odds ratios (ORs) for atypical fractures compared with the classic fracture group, with ORs of 44.7 (95% CI, 19.9-100.3) and 18.2 (95% CI, 2.9-112.3), respectively. Both [Actonel (risedronate)] and [Boniva (ibandronate)] were associated with a nonsignificant OR of 5.7 (95% CI, 0.5-64.7). Nevertheless, the 95% confidence intervals are wide, and it is therefore not possible to classify these agents according to this adverse effect. Regarding [Didronel (etidronate)] and [Zometa (zoledronic acid)], ORs could not be calculated because there were no patients treated with these agents in the atypical fracture group. Therefore, on the basis of our results, we cannot conclude that there is a potential risk of atypical fractures with [Actonel (risedronate)], [Boniva (ibandronate)], [Didronel (etidronate)], and [Zometa (zoledronic acid)] use, likely owing to a lack of statistical power. Indeed, these drugs were prescribed far less often than alendronate. However, some evidence is available in the literature.... [Footnote omitted]
In fact, here, we have heard from women who used Actonel, Boniva, and Fosamax (alone or is some sequential combination) for five years, at least, that have been diagnosed with single leg or bilateral low-stress atypical femur fractures -- albeit this is not the basis for a medical or scientific determination as regards this controversial and still developing drug-safety issue.______________________________________________________________________________