More older adults used multiple medications and dietary supplements, and taking them together put more people at increased risk for a major drug interaction, according to a new study published online by JAMA Internal Medicine.
Most older adults in the United States use prescription and over-the-counter medications and dietary supplements. There is increased risk among older adults for adverse drug events and polypharmacy.
Dima M. Qato, Pharm. D., M.P.H., Ph.D., of the University of Illinois at Chicago, and coauthors analyzed nationally representative data to examine changes in medication use, which included concurrent use of prescription and over-the counter medications and dietary supplements, to gauge potential for major drug interactions.
The study group included 2,351 participants in 2005-2006 and 2,206 in 2010-2011 who were between the ages of 62 and 85. In-home interviews and direct medication inspection were performed.
The authors report:
- Concurrent use of at least five prescription medications increased from 30.6 percent to 35.8 percent over the study period.
- Concurrent use of five or more medications or supplements of any type increased from 53.4 percent to 67.1 percent.
- Use of over-the-counter medications declined from 44.4 percent to 37.9 percent.
- Dietary supplement use increased from 51.8 percent to 63.7 percent. Multivitamin or mineral supplements and calcium were the most commonly used supplements during the study period.
- About 15.1 percent of older adults in 2010-2011 were at risk for a major drug interaction compared with an estimated 8.4 percent in 2005-2006. For example, preventive cardiovascular medications and supplements were increasingly used together in interacting drug regimens.