At least one in 25 older adults, about 2.2 million people in the United States, take multiple drugs in combinations that can produce a harmful drug-drug interaction, and half of these interactions involve a non-prescription medication, researchers from the University of Chicago Medical Center report in the Dec. 24/31, 2008, issue of JAMA.
Although the number of people taking medications has remained stable for the last decade, the number of drugs taken by older people has significantly increased. This may be because of more intense therapy for chronic illness, improved access to medications due to Medicare Part D, and the growth of the generic drug market. More than half of older adults now take five or more medications or supplements.
“Older adults are the largest consumer of prescription drugs,” said study author Stacy Tessler Lindau, MD, assistant professor of obstetrics and gynecology and of medicine at the University of Chicago Medical Center. “We find that they commonly combine these prescription medications with over-the-counter medications and dietary supplements, which can increase their vulnerability to medication side-effects and drug-drug interactions.”