USC study finds rising medication use and drug interaction risks in older Americans

A study from the University of Southern California, published in JAMA, reveals that polypharmacy among older Americans is increasing. Research analyzing adults aged 62 to 85 shows that the percentage of individuals taking five or more prescription medications rose from 31 percent to nearly 36 percent over the last decade.

Additionally, the use of multiple dietary supplements has grown from 12.6 percent to 16.7 percent. Despite a modest decline in the prevalence of potentially major drug-drug interactions—dropping from 25.7 percent to 22.3 percent—researchers warn that more than one in five older adults remains at risk for significant interactions. Common medication classes involved in these high-risk interactions include antidepressants, statins, and antiplatelet therapies.

Pharmacologists note that the simultaneous increase in prescribed medicines and dietary supplements adds complexity to the aging body’s chemical processing, creating significant pharmacological challenges.