Pharmacokinetics/pharmacodynamics of desloratadine and fluoxetine in healthy volunteers

J Clin Pharmacol. 2004 Nov;44(11):1252-9. doi: 10.1177/0091270004269518.

Abstract

The authors assessed the potential for a pharmacokinetic/pharmacodynamic interaction between desloratadine and fluoxetine. This randomized, placebo-controlled, open-label study was conducted in 54 healthy volunteers. Subjects received 1 of 3 treatments: desloratadine 5 mg plus fluoxetine 20 mg, desloratadine 5 mg plus placebo, or fluoxetine 20 mg plus placebo. Serial electrocardiograms (ECGs) were performed at baseline and day 35. Treatment effects on C(max) and AUC were assessed. During coadministration of desloratadine with fluoxetine, the ratio of the mean log-transformed C(max) and AUC values for desloratadine following concomitant fluoxetine therapy revealed a small increase in C(max) values of 15% (90% confidence interval [CI], 95%-139%) but no increase for AUC values (90% CI, 82%-123%). Corresponding values for 3-OH desloratadine demonstrated small increases in mean log-transformed C(max) and AUC ratios: 17% (90% CI, 100%-136%) and 13% (90% CI, 96%-132%), respectively. Statistical evaluation of the ratio of the mean C(max) and AUC values for fluoxetine following concomitant desloratadine therapy revealed small decreases of 9% (90% CI, 72%-115%) and 11% (90% CI, 69%-113%), respectively. Corresponding values for norfluoxetine demonstrated modest increases in mean log-transformed C(max) and AUC ratios: 22% (90% CI, 100%-139%) and 18% (90% CI, 101%-136%), respectively. Coadministration of desloratadine with a potent inhibitor of CYP2D6 did not result in clinically relevant changes in its pharmacokinetic parameters. Desloratadine administration was not associated with clinically important changes in the pharmacokinetics of fluoxetine, a drug metabolized by CYP2D6. The most common adverse event in all groups was headache (65%). Desloratadine plus fluoxetine caused no significant changes in ECGs or ventricular rate.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anti-Allergic Agents / adverse effects
  • Anti-Allergic Agents / pharmacokinetics
  • Anti-Allergic Agents / pharmacology*
  • Area Under Curve
  • Cytochrome P-450 CYP2D6 / metabolism
  • Cytochrome P-450 CYP2D6 Inhibitors
  • Electrocardiography
  • Female
  • Fluoxetine / adverse effects
  • Fluoxetine / analogs & derivatives*
  • Fluoxetine / blood
  • Fluoxetine / pharmacokinetics
  • Fluoxetine / pharmacology*
  • Histamine H1 Antagonists, Non-Sedating / adverse effects
  • Histamine H1 Antagonists, Non-Sedating / pharmacokinetics
  • Histamine H1 Antagonists, Non-Sedating / pharmacology*
  • Humans
  • Loratadine / adverse effects
  • Loratadine / analogs & derivatives*
  • Loratadine / blood
  • Loratadine / pharmacokinetics
  • Loratadine / pharmacology*
  • Male
  • Middle Aged
  • Serotonin Uptake Inhibitors / adverse effects
  • Serotonin Uptake Inhibitors / pharmacokinetics
  • Serotonin Uptake Inhibitors / pharmacology*

Substances

  • Anti-Allergic Agents
  • Cytochrome P-450 CYP2D6 Inhibitors
  • Histamine H1 Antagonists, Non-Sedating
  • Serotonin Uptake Inhibitors
  • Fluoxetine
  • 3-hydroxydesloratadine
  • Loratadine
  • Cytochrome P-450 CYP2D6
  • desloratadine
  • norfluoxetine