Itraconazole can cause a marked increase in
digoxin levels (usually doubled, but a 6-fold increase was seen in one case).
Toxicity may occur unless the
digoxin dosage is suitably reduced. Voriconazole and
posaconazole may interact similarly.
Monitor concurrent use for
digoxin toxicity (e.g. bradycardia or nausea), taking
digoxin levels as necessary. Adjust the dose accordingly. Note that, based on the interaction with
itraconazole, the manufacturer of
posaconazole advises monitor- ing
digoxin levels.