Introduction Azole antifungal drugs are commonly prescribed to treat invasive fungal infections in various disease conditions. However, these drugs are substrates and inhibitors of cytochrome P450 (CYP) enzymes, UGT1A4, and P-gp. The genetic variants of CYP3A4/5, CYP2C9, CYP2C19, ABCB1, or UGT1A4 can modify the safety or effectiveness of azole antifungals.