In vitro combination of antifungal drugs with tacrolimus (FK506) holds promise against clinical Candida species, including Candida auris

In vitro interactions between tacrolimus, a calcineurin inhibitor, and fluconazole, itraconazole, caspofungin, or anidulafungin were evaluated against Candida auris, C. albicans, C. parapsilosis, and C. glabrata (each five strains). Tacrolimus-itraconazole, tacrolimus-caspofungin, and tacrolimus-fluconazole combinations resulted in synergistic interactions against 95%, 90%, and 60% of Candida isolates, respectively. However, tacrolimus-anidulafungin resulted in only a 35% synergistic effect. A combination of tacrolimus and itraconazole was most potent with synergy against 100% of C. auris, C. parapsilosis, and C. glabrata isolates. Of note, no antagonistic interaction was found.