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K. SCHOOLAR REYNOLDS, Office of Clinical Pharmacology and Biopharmaceutics, U.S. Food & Drug Admin., 5600 Fishers Ln., HFD-880, Rockville, MD 20850 Interactions between drugs and food components present a number of scientific and regulatory challenges. The interactions are of interest because they can lead to serious adverse effects. However, many of the processes that protect consumers from interactions between two or more drugs are more difficult to achieve for interactions between food components and drugs. The processes are related to (1) screening for potential interactions, (2) the formal evaluation of interactions, (3) communication with health care providers, and (4) communication with the public. Screening for and the formal evaluation of interactions require us to understand the mechanisms of the interactions. The effect of grapefruit juice on CYP3A has been appreciated for a number of years. Documented interactions include increased plasma concentrations of calcium channel blockers, antihistamines, and statins when these drugs are administered with grapefruit juice. Newer evidence indicates that the effect may extend to drug transporters and that juices other than grapefruit juice may cause interactions. Drug characteristics also affect the potential for a serious interaction; grapefruit juice has a greater impact if a drug metabolized by CYP3A has low bioavailability and undergoes extensive first pass metabolism in the gut. Communication to health care providers and consumers regarding the clinical relevance of interactions between drugs and food is challenging. The drug label is an important tool for communication with health care providers. A number of factors (lack of controlled studies and lack of product standardization) complicate the labeling of interactions with food components. Because many health care providers do not have an accurate understanding of the significance of drug interactions with food components, it is difficult for consumers to appreciate the issue. This presentation will review how understanding the mechanistic basis of these interactions can facilitate their appropriate evaluation and accurate communication with health care providers and consumers.
Session 104, Food-drug interactions: A new challenge for phytochemical research and industry
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |