- Patients receiving any other medications that are contraindicated with the use of voriconazole i.e. terfenadine, long acting barbiturates, ergot alkaloids, etc. (Refer to SMPC). Only patients on rifampicin, rifabutin, phenytoin, and carbamazepine would have voriconazole precluded. Voriconazole influences with the pharmacokinetics of many additional agents- (see SMPC)- most importantly anti-rejection compounds- cyclosporine, tacrolimus]