A new study in JAMA Internal Medicine indicated that since 2005, the risk of major drug interaction in older adults has increased in those taking multiple prescriptions and dietary supplements concurrently.

An increased risk of adverse drug events and polypharmacy was observed in older adults that took both prescription and over-the-counter (OTC) drugs and dietary supplements. Researchers from the University of Illinois at Chicago evaluated nationally representative data to identify changes in medication use (concurrent prescription and OTC drugs and dietary supplements) to note possibilities for major drug interactions. 

A total of 2,351 patients in 2005–2006 and 2,206 patients in 2010–2011 aged 62–85 were included in the study. Study findings showed that concurrent use of ≥5 prescription medications increased from 30.6% to 35.8% over the study period. Similarly, concurrent use of ≥5 medications or supplements of any type rose from 53.4% to 67.1%.

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Use of OTC medications decreased from 44.4% to 37.9%. Dietary supplement use rose from 51.8% to 63.7% with multivitamin/mineral supplements and calcium being the most commonly used supplements during the study period.

About 15.1% of older adults in 2010–2011 were at risk for a major drug interaction vs. about 8.4% of older adults in 2005–2006. For example, this higher risk may be attributed to preventive cardiovascular therapies and supplements that were taken concomitantly in interacting drug regimens. Over the study period, clinically significant increases in use were seen with statins, antiplatelet drugs, and omega-3 fish oils.

Some study limitations include the inability to evaluate the various factors that can affect adverse drug events, including hepatic and renal function, interaction type, dosage, timing of concurrent use, and disease severity.

The authors concluded, “Therefore healthcare professionals should carefully consider the adverse effects of commonly used prescription and nonprescription medication combinations when treating older adults and counsel patients about these risks.” In a related commentary, Michael A. Steinman, MD, of the University of California, San Francisco, added that creating systems to support an ongoing process of medication monitoring is needed.”Such systems would help us periodically assess the benefits, harms and ongoing need for each of a patient’s medications, as well as the reasonableness of the medication regimen as a whole.”

A separate research letter published in JAMA Internal Medicine also found that many patients did not report their use of complementary and alternative medicine (CAM) to their primary care physicians. In the study (n=7,493), non-disclosure was most common among those who practiced yoga, tai chi, qi gong, mediation or mindfulness. The study noted physicians should consider “more actively inquiring about patients’ use of CAM, especially for modalities likely to be medically relevant.” 

For more information visit jamanetwork.com.