Predicted increase in the area under the codeine plasma concentration-time from coadministration of dextropropoxyphene, fluconazole, ketoconazole, or methadone

Drug (In Vivo Dose)aPredicted Fold Increase in AUC Ratio Based On:
Total Inhibitor ConcentrationbUnbound Inhibitor Concentrationb
Dextropropoxyphene (117 mg 8-hourlyc)1.831.26
Fluconazole (400 mg once dailyd)1.601.54
Ketoconazole (200 mg once dailye)2.971.04
Methadone (74 mg once dailyf)3.661.72