Study: Drug interactions may be imminent among antidepressant users

ANN ARBOR, Mich. — Many older Americans prescribed antidepressants may be taking medication that could adversely interact with the antidepressant, a new study found.

The Thomson Reuters study — sponsored by Sanofi-Aventis and published in the American Journal for Geriatric Psychiatry — found that there are more challenges in prescribing antidepressants to older Americans. Among 39,512 new antidepressant users ages 65 years and older, 25.4% were prescribed antidepressants and another medication that could cause a major interaction, while an additional 36.1% had potential moderate interactions. The remaining 38.5% of respondents had minor or no interactions.

What's more, the study found, the likelihood that users would have to switch antidepressants because of adverse interactions between medications was 19.5%. Many side effects reported by patients included insomnia, somnolence and drowsiness.

"We found a concerning degree of potentially harmful drug combinations being prescribed to seniors. These findings reinforce the need for clinicians to be aware of potential drug-drug interactions and the importance of close patients monitoring," said Tami Mark, the paper's lead author and director of analytic strategies at Thomson Reuters.