Related Experiment Video
Updated: Jul 11, 2026

Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
Published on: November 15, 2013
Pharmacokinetic interaction between ketoconazole and amprenavir after single doses in healthy men
R E Polk1, M A Crouch, D S Israel
1Department of Pharmacy, Virginia Commonwealth University/Medical College of Virginia Campus, Richmond, USA.
Study Objective:
To determine the effects of coadministration of amprenavir and ketoconazole on the pharmacokinetics of both drugs, and to assess the utility of the erythromycin breath test (ERMBT) to predict and explain these effects.
Design:
Open-label, randomized, balanced, single-dose, three-period crossover study.
Setting:
University research center.
Subjects:
Twelve healthy men.
Intervention:
Subjects received amprenavir 1200 mg, ketoconazole 400 mg, and amprenavir 1200 mg plus ketoconazole 400 mg. Each treatment was separated by 14 days.
Measurements And Main Results:
Serial plasma samples for amprenavir and ketoconazole concentrations were measured by high-performance liquid chromatography. Coadministration of the drugs increased amprenavir area under the curve extrapolated to infinity (AUCinfinity) by 31% and reduced its maximum concentration (Cmax) by 16%. Amprenavir increased the AUCinfinity of ketoconazole by 44% and increased the drug's half-life and Cmax by 23% and 19%, respectively. Both agents resulted in substantial inhibition of ERMBT.
Conclusion:
Coadministration of ketoconazole and amprenavir results in a statistically significant increase in AUC for both agents, but the changes are not likely to be clinically important.
Related Concept Videos
Dosage Regimens: Partial Pharmacokinetic Parameters
Pharmacokinetics: Drug–Drug Interactions
Pharmacokinetics: Drug–Food and Drug–Viral Interactions
Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment
Pharmacokinetic–Pharmacodynamic Relationship: Duration of Dose-Effect Relationship
Pharmacokinetic–Pharmacodynamic Relationship: Intensity of Dose-Effect Relationship

