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Fluconazole

Interaction with Vardenafil

Monitor therapy
QT risk: Fluconazole Vardenafil

Effect: Fluconazole may increase the plasma concentrations of vardenafil.

Clinical management: Caution should be exercised upon coadministration of these drugs. Monitor for increased vardenafil adverse events (e.g. headache, flushing, priapism, visual disturbance, hypotension).

Probable mechanism: Inhibition of the cytochrome P450 (CYP) 3A4-mediated biotransformation by fluconazole.

Summary: Although not studied for fluconazole, coadministration of ketoconazole (200 mg/day, strong CYP3A4-inhibitor) increased the AUC and Cmax of vardenafil (5 mg, single dose) by 10-fold and 4-fold, respectively. Coadministration with the CYP3A4 inhibitor fluconazole could result in similar effects. 

QT effect

Fluconazole: QT risk

Substantial evidence reports that this drug prolongs the QT interval and has a risk of causing TdP (when used as directed in labeling).

References

Vardenafil: Possible QT risk

Substantial evidence reports that this drug causes QT prolongation, but there is insufficient evidence that this drug has a risk of causing TdP (when used as directed in labeling).

References

  • SPC Vardenafil