Ketoconazole,
itraconazole,
posaconazole and
voriconazole may increase the levels of
ergot derivatives such as ergotamine, dihydroergotamine, and methysergide, which may result in ergotism. Other
azoles, such as
fluconazole, may interact similarly, although to a lesser extent.
The UK manufacturers of various
ergot derivatives contraindicate use with all azole antifungals. The US manufacturers of ergotamine and dihydroergotamine advise caution with
fluconazole and
clotrimazole, which are moderate CYP3A4 inhibitors. Any patient taking an ergot derivative with an azole should be closely monitored for signs of ergotism.