Effect: Voriconazole may increase the plasma concentrations of celecoxib.
Clinical management: Caution should be exercised upon coadministration of these drugs. Monitor for increased celecoxib toxicity and adjust dose if necessary.
Probable mechanism: Inhibition of the cytochrome P450 (CYP) 2C9-mediated biotransformation by voriconazole.
Summary: Although not studied for celecoxib, coadministration of voriconazole and ibuprofen/diclofenac (both CYP2C9 substrates) in two seperate single dose drug interaction studies resulted in increased AUC and Cmax for both NSAIDs. Coadministration with the CYP2C9 substrate celecoxib could result in similar effects. Moreover, fluconazole (also a CYP2C9 inhibitor) increased celecoxib AUC and Cmax by 130/134% and 60/68% in two seperate studies.
QT effectVoriconazole: Conditional QT risk
Substantial evidence reports that this drug causes QT prolongation and has a risk of TdP, but only under certain known conditions (e.g. excessive dose, drug interaction, etc.).