Effect: Voriconazole may increase the plasma concentrations of ergot derivates (e.g. ergoloid mesylates).
Clinical management: Avoid concurrent use of voriconazole and ergot derivates. If concomitant use is required, carefully monitor for increased risk of ergotism (excessive vasoconstriction in the extremities, convulsions, GI/CNS effects).
Probable mechanism: Inhibition of the cytochrome P450 (CYP) 3A4-mediated biotransformation by voriconazole.
Summary: Although not studied clinically, coadministration of the CYP3A4 inhibitor voriconazole and ergot derivates (dihydroergotamine, ergotamine, ergoloid mesylates, ergometrine, methylergometrine, methysergide) may result in increased plasma concentrations of the ergot derivate. Hence, combination of triazoles known to strongly inhibit CYP3A4 (itraconazole, posaconazole and voriconazole) and ergot derivates is contraindicated (unlike the moderate CYP3A4 inhibitor fluconazole).
- SPC Ergotamine
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.).