- 1Lawson Health Research Institute (Lawson Health Research Institute), London, Canada
- 2The Russian Peoples' Friendship University, Moscow, Russia
Summary. This mini-review discusses key scientific concepts and clinical implications of grapefruit-drug interactions. Grapefruit and certain related citrus fruits (Seville orange, pomelo, lime) are foods considered to be healthful but having the potential for a pharmacokinetic interaction causing enhanced oral bioavailability of certain drugs. The active constituents are most likely furanocoumarins. Varieties of sweet oranges neither contain furanocoumarins nor produce this interaction. The interaction involves irreversible inactivation of the enzyme CYP 3A4 involved in the metabolism of many drugs. The key issues are adverse effects occurring in routine clinical practice; some of them are discussed here. While grapefruit-drug interactions are generally considered to be negative occurrences to be avoided, there has been consideration to use this interaction to achieve beneficial therapeutic goals i.e. lowering of drug dosages. Unfortunately, the effect has been highly variable among individuals and studies. Development of a standard drug on the basis of furanocoumarins may be a solution. In conclusion, grapefruit and certain other citrus fruits have the potential for an interaction causing enhanced bioavailability of some oral drugs. This action carries the risk of adverse events from excessive effect, particularly for drugs with overdose toxicities. This necessitates an understanding of this interaction and the application of such in the safe and effective use of drugs in general practice. Key words: grapefruit, pharmacotherapy, pharmacokinetics, drug interaction, nutrition.