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In 1991, I researched and compiled the information for the Reference Guide to Drug-Nutrient Interactions published by the BC Dietitians and Nutritionists Association.1 At that time, a short report by Canadian researchers Bailey et al. appeared in the Lancet claiming a drug interaction between grapefruit juice (GJ) and the calcium-channel blockers, felodipine (RenedilŪ, PlendilŪ) and nifedipine (AdalatŪ).2 The effect appeared specific to GJ, as no interaction was detected between orange juice and either felodipine or nifedipine. This phenomenon was first discovered by chance in an ethanol-drug interaction study done in 1989 by the same authors, using GJ as the vehicle for the alcohol used in the study.3 Numerous other reports have since appeared in the literature regarding GJ interactions with other drugs and their clinical significance, along with attempts to determine the component(s) of GJ that is the source of the interaction. The authors of the first report have since published many articles4,7,11,21-23, 26, 70, 83, 95, 106 in this field of research. The clinical significance of the GJ interaction with each particular drug depends on the magnitude of change in the drug pharmacokinetic profile, drug concentration-response relationships, and individual patient response.4 When reviewing the studies presented here, one must keep in mind that many of the studies were done in healthy subjects, taking only the study medication. Effects may differ in patients with specific conditions or taking other medications than those studied. Also, many early studies were done in small groups of individuals, often in an open, non-blinded manner. |
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| Last Updated: May 04, 2005 |
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