GRAPEFRUIT JUICE AND DRUGS - HOW SIGNIFICANT IS THE INTERACTION

The serendipitous finding that grapefruit juice interacts with felodipine was subsequently found to be valid for some other dihydropyridines, but this interaction is probably not limited to this class of drugs. The clinical relevance of the grapefruit juice interaction with each particular drug will depend on the magnitude of change in the pharmacokinetic profile of the drug, the drug concentration-response relationships and the patient. Since current information indicates that the interaction is variable and unpredictable, it appears reasonable to caution patients not to ingest grapefruit juice at the same time as taking felodipine and other dihydropyridines. Identification of the active ingredient in grapefruit juice may allow the prediction of other foods that may also interact with dihydropyridines and some other drugs. Furthermore, it may lead to exploitation of the inhibitory effects of the active ingredient(s), and its inclusion into drug formulations to increase the clinical efficacy of orally administered drugs. It seems that this discovery has provided fundamental new knowledge both to improve pharmacotherapy and to stimulate further research. © 1994, Adis International Limited. All rights reserved.