May increase plasma concentrations of oral hypoglycaemics (e.g. tolbutamide, glyburide, glipizide), phenytoin, theophylline, tofacitinib, rifabutin. May increase prothrombin time w/ anticoagulants. May cause significant increase in ciclosporin levels in renal transplant patients w/ or w/o renal impairment. Rifampicin reduces fluconazole levels. May increase risk of nephrotoxicity w/ tacrolimus. May increase the effect of short-acting benzodiazepines (e.g. midazolam).
Potentially Fatal: Increased risk of cardiac arrhythmias or QT prolongation w/ terfenadine, cisapride, astemizole, pimozide, quinidine, halofantrine and erythromycin.