Physicians may have to rethink prescribing SSRIs to their patients who are over the age of 50.
Three studies appearing in the Archives of Internal Medicine suggest a link between the use of selective serotonin reuptake inhibitors--including Prozac, Paxil, Lexapro, and Zoloft--and an increase in fractures in both men and women over 50.
"Because depression itself is associated with an increased risk for bone loss in older people, a better understanding of the impact of antidepressants on bone is urgently needed," wrote Kenneth Saag in "Mind the Mind, but Mind the Bones!" in the June 25 issue of journal. The report also noted that depression affects as many as 40 percent of adults over 55. Saag's concern regarding prescribing SSRIs was echoed by a second report noting that the use of SSRIs was associated with an increased rate of bone loss in the hip in women (average age at onset was 78.5). This same study noted that bone loss did not occur with the use of TCAs, or tricyclics, an older class of antidepressants.
But there's a catch. Unfortunately, simply switching patients to TCAs may not be the answer.
"Because of concerns about the arrhythmogenic potential of TCAs, there is a strong preference for SSRIs in older adults in whom depression commonly coincides with heart disease," Saag writes.
To add to the confusion, the mechanism behind SSRIs and bone loss has not been clearly identified. Recent studies have shown a direct link between calcium consumption and bone formation in pre-adolescents, which begs the question of whether younger patients taking SSRI have an increased lifetime risk for bone loss.
Manufacturers of SSRIs will no doubt consider this dilemma and the economic fallout from this research.
"While Lilly supports efforts to learn more about this class of medications, due to the inherent, uncontrolled variables between the SSRI user and non-user groups, a causal relationship cannot be established between SSRI use and bone loss," said Charles McAtee, spokesman for Eli Lilly.
"The current Prozac product label lists 'osteoporosis' as an adverse event occurring on a rare basis--less than 1 in 10,000 patients, based upon data from clinical trials. Decisions concerning the potential risk vs. benefit of using any medication should be made with the advice of a physician who is well-informed about the patient's medical history. As a side note, many studies show that osteoporosis and depression often coexist," McAtee added.