Insights into Drug-Related Interactions in Older Adults

In a recent cross-sectional study, researchers evaluated the prevalence of possible drug–disease and drug–drug interactions and associated variables in community-dwelling older adults.¹ Patients aged 70–79 years (n=3,055) without mobility limitation at their baseline visit in the Health Aging and Body Composition Study were enrolled in this study.

Outcome factors were potential drug–disease and drug–drug interactions identified by using particular criteria from various sources, as well as self-reported non-prescription and prescription drug use. Explicit criteria for 70 potential drug–drug interactions developed by geriatric experts and reactions found to be a cause for drug-related hospitalizations were used.

The findings showed that 34% of patients (34.1%) had at least one interaction, while 25.1% had at least one drug–drug interaction. Also, 10.7% of patients who had a drug–drug interaction involved a non-prescription drug. Sixteen percent of patients had a potential drug–disease interaction, with at least 37% of those reactions involving a non-prescription drug.

Non-steroidal anti-inflammatory drugs (NSAIDs) and anti-hypertensive agents were the most common drug–drug interaction. Aspirin/NSAID use in patients with a history of peptic ulcer disease without the use of gastro-protection (4.3%) was the most common drug–disease interaction. Having a history of falls or fractures and taking one of five central nervous system medication classes (4%; e.g., anticonvulsants, antipsychotics, SSRIs, TCAs, benzodiazepine receptor agonists) was the second most common drug–disease interaction.

Two factors were associated with drug interactions: a history of hospitalization in the prior year and the number of medications used. The use of each prescription drug raised the likelihood of having at least one type of drug interaction by 35–40%. In patients with a prior hospitalization, hospitalization raised the odds of having at least one type of drug interaction by 49–84%.

The authors write that the ability to generalize this study to the older U.S. population may be limited because the study participants did not have mobility issues, heart failure or chronic kidney disease. Thus, the rate of drug interactions observed in this study may be low. More research is needed in this area, especially in patients with more comorbidities.

Michele B. Kaufman, PharmD, BCGP, is a freelance medical writer based in New York City and a pharmacist at New York Presbyterian Lower Manhattan Hospital.

Reference

1. Hanlon JT, Perera S, Newman AB, et al. Potential drug–drug and drug–disease interactions in well-functioning community-dwelling older adults. J Clin Pharm Ther. 2017 Jan 22. doi: 10.1111/jcpt.12502. [Epub ahead of print]