Interaction between grapefruit juice and diazepam in humans

  • M. Özdemir
  • Y. Aktan
  • B. S. Boydaĝ
  • M. I. Cingi
  • A. Musmul
Article

DOI: 10.1007/BF03189827

Cite this article as:
Özdemir, M., Aktan, Y., Boydaĝ, B.S. et al. European Journal of Drug Metabolism and Pharmacokinetics (1998) 23: 55. doi:10.1007/BF03189827

Summary

Grapefruit juice has been reported to markedly improve the bioavailability of triazolam, midazolam, terfenadine, cyclosporine and several dihydropyridine calcium channel blockers including felodipine, nifedipine, nitrendipine and nisoldipine. Because these drugs are metabolized by the hepatic cytochrome P450 isozyme (CYP) 3A4, the inhibitory effect of grapefruit juice is thought to results from inhibition of CYP3A4. In this study, our aim was to investigate the effects of grapefruit juice on plasma concentrations of diazepam. Eight healthy male and female subjects participated in this study. Oral (5 mg) diazepam was administered with either 250 ml water and grapefruit juice. Blood samples were collected for a 24 h period, and whole blood concentrations of diazepam were measured enzyme immunoassay. The mean AUC(0−24) of diazepam was increased 3.2-fold (P<0.001) and Cmax was increased 1.5-fold (P<0.05) by the grapefruit juice. Grapefruit juice postponed the tmax of diazepam from 1.50 h to 2.06 h (P<0.01).

Keywords

Beverages citrus-fruits diazepam-pharmacokinetics cytochrome P-450-metabolism food-drug interactions 

Copyright information

© Springer-Verlag 1998

Authors and Affiliations

  • M. Özdemir
    • 1
  • Y. Aktan
    • 1
  • B. S. Boydaĝ
    • 1
  • M. I. Cingi
    • 1
  • A. Musmul
    • 1
  1. 1.Department of Pharmacology, Medical FacultyUniversity of OsmangaziEskisehirTurkey

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