More than one in five older Americans are taking combinations of medications that could lead to major drug interactions, despite a modest decline in such risks over recent years, according to a new study published in JAMA.
The findings, based on nationally representative data from almost 5,000 U.S. adults aged 62 to 85, come as researchers report that older Americans are increasingly taking multiple prescription drugs and dietary supplements simultaneously.
Independent experts say the trend raises ongoing concerns about medication safety, side effects and preventable hospitalizations among an aging population.
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“Patients who have several chronic illnesses are inevitably treated with complicated regimens,” Dr. Spencer Kroll, a physician with expertise in pharmacology, told Newsweek. “It is encouraging to see that the number of people exposed to potentially serious drug-drug interactions is down.”
He added: “But the number exposed remains well over one-fifth of the elderly. This persistence is a major public health challenge, especially in geriatric care.”
Newsweek contacted the study authors by email for additional comment.
Growing Use of Multiple Medications
The study, led by Dima Mazen Qato of the USC Mann School of Pharmacy and Pharmaceutical Sciences and the USC Schaeffer Center for Health Policy and Economics, analyzed data from the National Social Life, Health and Aging Project, which is supported by the National Institute on Aging.
Researchers compared medication and supplement use among older adults in 2015-2016 with use in 2021-2023.
They found that polypharmacy, defined as taking five or more prescription medications at the same time, increased from 31 percent to 35.7 percent.
At the same time, dietary supplement polypharmacy rose from 12.6 percent to 16.7 percent.
Kroll said the increase in overall medication use is one of the study’s most important findings.
“The data show a significant growth in the simultaneous use of five or more prescribed medicines and dietary preparations,” he told Newsweek. “From a pharmacological point of view, this is alarming because each additional chemical entity increases the pharmacokinetic and pharmacodynamic complexity of the aging body.”
He added that as medication regimens become more complex, the risks also grow, including side effects and unplanned hospitalizations.
“With each added medication for a patient, the consequences of drug-drug interactions increases exponentially,” he said.
Interaction Risks Remain High
Although the prevalence of potentially major drug-drug interactions declined from 25.7 percent to 22.3 percent during the study period, researchers noted that more than one in five older adults remained at risk in 2021-2023.
The medication classes most often involved in potentially major interactions changed little over time. Antidepressants, statins and antiplatelet therapies were the most commonly used medications appearing in high-risk combinations.
Kroll said the finding is particularly significant because all three categories are widely used and often medically necessary.
“These are essential medicines for managing the health of the cardiovascular system and the mental health in older populations, so we can’t avoid them,” he said. “But it also requires the greatest caution because interactions between these drug classes can lead to severe complications, such as increased bleeding and reduced metabolism.”
Reduced metabolism can increase the likelihood of toxicity and patient harm, even when medications are prescribed appropriately to improve health outcomes, he added.
In a statement accompanying the study, Qato said: “These findings underscore the need for continuing efforts to improve medication safety among older adults. Efforts to reduce polypharmacy and harmful drug interactions should focus on commonly used interacting regimens, particularly those involving antidepressants.”
Kroll also pointed to broader challenges within the health care system, including fragmented care across multiple physicians, pharmacies and hospital networks. He said older patients often do not receive a comprehensive review of all the medications they take, while electronic medical record systems frequently fail to communicate with one another.
“As the population grows older, our patients’ health and independence will depend increasingly on the ability to negotiate these complex interactions in a safe and sensible manner,” he said, describing the findings as a call for physicians to rethink how medications are prescribed and managed in older adults.
Reference
Qato, D.M., Wilder J., Ondanat Veetil S.K., et al. (2026). Polypharmacy and Drug-Drug Interactions Among Older Adults. JAMA. doi: 10.1001/jama.2026.17268.
Contact Newsweek editors on this story: Kara Dolman and Shakeema Edwards.