Isavuconazole is an triazole antifungal with broad spectrum of activity and good safety profile [A32026]. It is approved by the FDA and EMA for the treatment of invasive aspergillosis and mucormycosis. It works by inhibiting fungal cell membrane synthesis. Invasive fungal infections pose significant clinical challenges for patients, especially those who are immunocompromised. In vitro, most of the _Candida_ species, most _Aspergillus_ species, Mucorales, _Cryptococcus_ spp., _Fusarium_ species, dermatophytes and dimorphic fungi displayed susceptibility to isavuconzaole [A32029]. Resistance to isavuconazole has been associated with the mutation in the target gene CYP51 [FDA Label]. Cross-resistance between isavuconazole and other azoles was also proposed although the clinical relevance is unclear [FDA Label]. As isavuconazole displays low water solubility, it is found as an active ingredient of its prodrug, [DB06636]. The prodrug formulation of isavuconazole is FDA- and EMA-approved and is marketed under the trade name Cresemba for the treatment of invasive aspergillosis and mucormycosis as oral or intravenous administration. The intravenous formulation is cyclodextrin-free which gives isavuconazole an advantage over other azole antifungals that requires cyclodextrin for facilitating drug solubility; this is because cyclodextrin has a potential for nephrotoxicity [A32029]. It is proposed that the intravenous and oral dosing can be used interchangeably [L1482], without the need for a repeat loading dose when transitioning from an IV to an oral formulation [A32026]. Isavuconazonium displays excellent water solubility for intravenous formulations, good absorption, and enhanced oral bioavailability [A32026]. Following administration, isavuconazonium undergoes biotransformation to form the active moiety, isavuconazole, for the antifungal actions.