Complementary and Alternative Medicine: Dietary Supplement Interactions with Medication

Abstract

The potential for interaction between dietary supplements and medications has been reported to range from as low as 21% to as high as 46% in recent studies evaluating concomitant use. Despite a high rate of dietary supplement interactions with medications, it may be as few as 29% that have clinical significance, and these can be attributed to a small number of dietary supplements that account for 68% of all interactions identified in one report. Familiarity with this information is important to geriatric care givers and providers, because of the increasing prevalence of dietary supplement use with age and disposable income. In a survey of older adults on the United States–Mexico border, authors reported that 38.5% were taking 5 or more medications, and 16.2% of these were taking 2 or more dietary supplements. Among the older adults taking medications and dietary supplements, 49% were at risk of a drug–drug interaction and 31.5% were at risk of a dietary supplement–drug interaction. Usage of dietary supplements was evaluated in a cross-sectional sample of assisted living residents, aged 84.8 years with an average of 10 years of education, from 2 facilities in Washington and Oregon. On average, residents used 3.4 dietary supplements. The potential for misuse was identified in 51%, duplication between supplements or with medications was identified in 70% of residents and potential drug–disease–dietary supplement interaction was present in 21%. Forty percent of these residents turned to nurses or physicians for information regarding dietary supplements, just behind family and friends (49%). In the Mayo Clinic outpatient population of 1795 adults averaging 55 years of age, there were 107 dietary supplement–drug interactions of potential clinical significance identified in 710