Under-hyped and Over-hyped Drug-dietary Supplement Interactions and Issues

Mark A. Moyad, MD


Urol Nurs. 2010;30(1):85-87. 

In This Article

Abstract and Introduction


Complementary and alternative medicine utilization continues to abound, as does the use of prescription medications. Thus, real and hypothetical concerns exist for potential drug-dietary supplement interactions. Several supplements, including kava and St. John's Wort, have the potential for adverse medication interactions, but there are also several supplements, such as fish oil, garlic, ginkgo, pygeum, and saw palmetto, whose adverse potential may have been embellished. Still, there are other common supplements, such as vitamin D, that are enjoying an impressive amount of attention and consumption but their potential for current or future toxicity seems considerable and concerning, especially with individuals with multiple non-communicating practitioners. Regardless, it is important to continue to monitor dietary supplements (not just herbal products) that may have interaction and toxicity issues, and to also educate patients and clinicians on other supplements that do not have these issues despite an earlier concern and avoidance based on a minimal number of laboratory studies or case reports.


A total of 34 billion dollars a year is spent on complementary and alternative medicine (CAM) in the U.S. alone (Nahin, Barnes, Stussman, & Bloom, 2009). This reflects an increase of more than 25% in this past decade according to a re c e n t 2009 survey of 23,000 American adults by the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH) (Nahin, 2001). All age groups use CAM, and almost 40% of adults and 12% of children have used them in the past year. The majority of the expense on CAM (22 billion dollars) is directed toward "self-care," or treatments such as homeopathic medications and dietary supplements, sometimes purchased without physician approval or guidance. In fact, only one-third of patients tell their physicians about their dietary supplement use (Kennedy, Wang, & Wu, 2008). Surveys suggest that the potential for a negative drug-supplement interaction in patients has been found to be as high as 40% (Bush et al., 2007).


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