Drug interactions grapefruit

Fukuda K, Guo L, Ohashi N, Yoshikawa M, Yamazoe Y. Amounts and variation in grapefruit juice of the main components causing grapefruit-drug interactions. J Chromatogr 2000 741(B) 195-203. 

Regarding interactions between citrus and OATP, data from in vitro, animal and also human clinical studies are available. These studies demonstrated the inhibition of OATP-A in HeLa cells and of OATP-B mediated uptake of estrone-3-sulfate in human embryonic kidney cells and also in the oral intake of fexofenadine in rats by fruit juices, including GFJ and orange juice. Human clinical trials suggest a potential role of OATP in grapefruit-drug interactions using fexofenadine as substrate (22,23,67,78,79). 

Two reports of human clinical trials discuss the potential role of OATP in grapefruit-drug interactions using fexofenadine as substrate. These... 

Table 2 Drugs for Which Grapefruit-Drug Interactions Have Been Investigated... 

Mertens-Talcott SU, Zadezensky I, De Castro WV, et al. Grapefruit-drug interactions can interactions with drugs be avoided J Clin Pharmacol 2006 46 1390-1416. 

Fuhr, U. (1998). Drug interactions with grapefruit juice. Extent, probable mechanism and clinical relevance. DrugSaf., 18, 251-72. 

Fukuda, K.,Ohra, T. 8cYamazoe,Y. (1997). Grapefruit component interacting with rat andhuman P450 CYP3A possible involvement on non-flavonoid components in drug interaction. Biol. Pharm. Bull, 20, 560-4. 

DG Bailey, JMO Arnold, JD Spence. Inhibitors in the diet grapefruit juice-drug interactions. In RH Levy, KE Thummel, WE Trager, PD Hansten, M Eichelbaum, eds. Metabolic Drug Interactions New York Lippincott Williams Wilkins, 2000, pp. 661-667. 

Amlodipine shows a preference for binding vascular smooth muscle cells over cardiac muscle cells, thus acting as a peripheral arterial vasodilator (Pfizer, Inc. 2005). Like most other CCB dihydropyridines, amlodipine is highly protein bound and heavily metabolized. In contrast to felodipine, this compound is not influenced by grapefruit juice and appears to show fewer drug-drug interactions. 

Spence ID. Drug interactions with grapefruit juice whose responsibility is it to warm the public . Chn Pharmacol Ther 1997 61(4) 395-400. 

Ameer, B. and Weintraub, R.A. (1997) Drug interactions with grapefruit juice. Clin Pharmacokinet 33 103-121. 

Fuhr, U. and Kummert, A.L., The fate of naringin in humans a key to grapefruit juice-drug interactions, Clin. Pharm. Ther., 58, 365, 1995. 

Greenblatt, D J., Patki, K.C., Von Moltke, L.L., Shader, R.I. Drug interactions with grapefruit juice an update. J. Clin. Psychopharmacol. 21, 357-359, 2001. 

Huang SM, Hall SD, Watkins P, et al. Drug interactions with herbal products and grapefruit juice a conference report. Clin Pharmacol Ther 2004 75(1) 1-12. 

Fukuda K, Ohta T, Oshima Y, Ohashi N, Yoshikawa M, Yamazoe Y. Specific CYP3A4 inhibitors in grapefruit juice furocoumarin dimmers as components of drug interaction. Pharmacogenetics 1997 7 391-396. 

Drug Interactions of Grapefruit and Other Citrus—What Have We Learned ... 

PHENOLIC COMPOUNDS IN GRAPEFRUIT AND CITRUS WITH POTENTIAL DRUG INTERACTIONS... 

For several phenolics from citrus, such as eriocitrin, poncirin, and sinapic acid and anthocyanins, which occur in red grapefruit varieties and blood oranges, no specific drug interactions and also no interactions with CYP3A4 and P-gp are reported. 

The clinical relevance of data obtained from studies with single compounds is questionable, because most studies were performed in in vitro systems, limiting the predictability of the effects of the examined compounds in vivo. Moreover, some polyphenolics, such as quercetin, were shown to interact with the absorption or metabolism of drugs only at very high concentrations (50-100 pmol/L), which are likely to exceed the expected in vivo concentration after the consumption of a moderate amount of a grapefruit/ citrus product. Also, flavonoids have been demonstrated to potentially induce apoptosis in cell lines at concentrations comparable to those used for some in vitro drug interaction studies (64-66). This potentially could have impaired the investigation of enzyme and transporter activities. 

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