Effects of single and multiple doses of itraconazole on the pharmacokinetics of fexofenadine, a substrate of P-glycoprotein

Br J Clin Pharmacol. 2006 Sep;62(3):372-6. doi: 10.1111/j.1365-2125.2006.02689.x. Epub 2006 Jun 23.

Abstract

Aims: We determined whether or not the extent of drug interaction of fexofenadine by itraconazole is time-dependent.

Methods: In a randomized two-phase crossover study, itraconazole was administered orally for 6 days, and, on days 1, 3 and 6, fexofenadine was administered simultaneously. On another occasion, fexofenadine was administered alone.

Results: Itraconazole increased fexofenadine AUC(0, infinity), and the % change for difference was 178% (95% CI 1235, 3379), 205% (95% CI 1539, 3319) and 169% (95% CI 1128, 2987) on days 1, 3 and 6 of the 6 day treatment, respectively.

Conclusions: The extent of drug interaction by itraconazole was not time-dependent.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antifungal Agents / administration & dosage*
  • Antifungal Agents / pharmacology
  • Cross-Over Studies
  • Drug Interactions
  • Female
  • Histamine H1 Antagonists, Non-Sedating / pharmacokinetics*
  • Humans
  • Itraconazole / administration & dosage*
  • Itraconazole / pharmacology
  • Japan
  • Male
  • Terfenadine / analogs & derivatives*
  • Terfenadine / pharmacokinetics

Substances

  • Antifungal Agents
  • Histamine H1 Antagonists, Non-Sedating
  • Itraconazole
  • Terfenadine
  • fexofenadine