Taking Antidepressants Leads to More Bone Loss in Elderly
As many as 40 percent of older adults suffer from depression—often alongside other health conditions like heart disease, cancer, and Alzheimer's—and many turn to antidepressants to help lift their mood. Yet, two new studies linking antidepressants with bone loss may give them pause. Both studies, published in today's Archives of Internal Medicine, found that seniors who use selective serotonin reuptake inhibitors (i.e., Prozac, Paxil, Zoloft) had more bone loss compared with those who don't use the drugs. Those taking an older class of antidepressants, called tricyclics, did not suffer the added bone loss. SSRI medications may interact with certain receptors on bone cells, triggering the cells to release calcium at a faster rate, says Susan Diem, an assistant professor of medicine at the University of Minnesota who was involved in both studies.
The findings are striking: In one study of more than 2,700 women over age 65, hip bone density decreased 0.82 percent per year in SSRI users and decreased 0.47 percent per year in nonusers and those on tricyclics. In the second study of nearly 6,000 elderly men, SSRI users had a 4 percent lower bone density in their hip and a 6 percent lower density in their spine compared with those who weren't on the drugs. "We don't know, though, whether this increase in bone loss translates into an increased risk of fractures, and that's what really is important," stresses Diem.
Diem warns against stopping antidepressants based on the study results because depression itself can also lead to bone loss. In fact, the women's study found that the difference in bone loss rates grew smaller when those currently experiencing depression symptoms were excluded from the SSRI and nonuser groups. More important, the drugs may be a necessity for those with chronic depression who risk a recurrence or even suicide if they stop their medications. Switching to a tricyclic isn't a great option since those drugs often cause dry mouth, sedation, and reductions in blood pressure that can lead to falls.
These findings should, however, give patients and doctors a reality check reminding them that antidepressants affect all body systems, not just brain chemistry. While the Food and Drug Administration already requires black box warnings on SSRIs because of a potentially increased risk of suicidal tendencies in young users, the drugs have been deemed to be very safe in older users up until now. The possibility of accelerated bone loss should be a factor taken into account before the drugs are prescribed, and monitoring with regular bone density scans may be warranted for those who take these drugs for more than a few months, according to Kenneth Saag, an associate professor of medicine at the University of Alabama-Birmingham School of Medicine, who wrote the editorial accompanying the studies. (No studies have yet been done to see whether bone-building medications like Fosamax can counter the effects of antidepressants.)
Other experts question whether the drugs are being overprescribed in the elderly, many of whom may be depressed from the aging process rather than imbalanced brain chemicals. "We've found that psychotherapy works as well as medication in most cases," says Jerome Wakefield, a psychology researcher at New York University and author of The Loss of Sadness, "and, unlike drugs, it will attempt to address issues that are the source of sadness such as losses of loved ones or chronic health problems."