Use of Prescription and Over-the-counter Medications and Dietary Supplements Among Older Adults in the United States

Context Despite concerns about drug safety, current information on older adults' use of prescription and over- the- counter medications and dietary supplements is limited. Objective To estimate the prevalence and patterns of medication use among older adults ( including concurrent use), and potential major drug- drug interactions. Design, Setting, and Participants Three thousand five community- residing individuals, aged 57 through 85 years, were drawn from a cross- sectional, nationally representative probability sample of the United States. In- home interviews, including medication logs, were administered between June 2005 and March 2006. Medication use was defined as prescription, over- the- counter, and dietary supplements used "on a regular schedule, like every day or every week." Concurrent use was defined as the regular use of at least 2 medications. Main Outcome Measure Population estimates of the prevalence of medication use, concurrent use, and potential major drug- drug interactions, stratified by age group and gender. Results The unweighted survey response rate was 74.8% ( weighted response rate, 75.5%). Eighty- one percent ( 95% confidence interval [ CI], 79.4%- 83.5%) used at least 1 prescription medication, 42% ( 95% CI, 39.7%- 44.8%) used at least 1 over- the-counter medication, and 49%( 95% CI, 46.2%- 52.7%) used a dietary supplement. Twenty-nine percent ( 95% CI, 26.6%- 30.6%) used at least 5 prescription medications concurrently; this was highest among men ( 37.1%; 95% CI, 31.7%- 42.4%) and women( 36.0%; 95% CI, 30.2%- 41.9%) aged 75 to 85 years. Among prescription medication users, concurrent use of over- the- counter medications was 46%( 95% CI, 43.4%- 49.1%) and concurrent use of dietary supplements was 52% ( 95% CI, 48.8%- 55.5%). Overall, 4% of individuals were potentially at risk of having a major drug- drug interaction; half of these involved the use of nonprescription medications. These regimens were most prevalent among men in the oldest age group ( 10%; 95% CI, 6.4%- 13.7%) and nearly half involved anticoagulants. No contraindicated concurrent drug use was identified. Conclusions In this sample of community- dwelling older adults, prescription and nonprescription medications were commonly used together, with nearly 1 in 25 individuals potentially at risk for a major drug- drug interaction.