ANN ARBOR, Mich., Dec. 17, 2010 /PRNewswire/ — More than half
of older Americans who were prescribed antidepressants for the
first time were already taking a medication that could adversely
interact with the antidepressant, according to a new study
from Thomson Reuters.
For one-fourth of the seniors in the study, these were
potentially major drug interactions.
The research, published by the American Journal for Geriatric
Psychiatry, illustrates the complexity and challenges of
prescribing antidepressants to older patients.
“We found a concerning degree of potentially harmful drug
combinations being prescribed to seniors,” said Tami Mark, Ph.D.,
the paper’s lead author and director of analytic strategies at
Among the 39,512 new antidepressant users in the study, 25.4
percent were prescribed antidepressants and another medication that
could cause a major interaction. An additional 36.1 percent had
potential moderate interactions and 38.5 percent had minor or no
Pain medications were most often identified as having the
potential for major interactions with antidepressants, accounting
for more than one quarter of all potential major interactions among
seniors in the study.
“These findings reinforce the need for clinicians to be aware of
potential drug-drug interactions and the importance of close
patients monitoring,” Mark said.
The presence of contraindications or interactions increased the
probability of patients switching antidepressants by 19.5 percent.
The study also found that 5.6 percent of study subjects had a
documented side effect from the antidepressants they were
prescribed, most often insomnia, somnolence and drowsiness.
Overall, the presence of a side effect was associated with a 4.7
percentage point increase in drug switching (from 16.5% to 21.7%)
and a 3.7 percentage point increase in discontinuation of treatment
(from 22% to 25.7%).