Hydroxy Itraconazole (Itraconazole metabolite Hydroxy Itraconazole; R-63373) is an active metabolite of Itraconazole (ITZ), a triazole antifungal agent. It has antifungal activity in vitro and in vivo, inhibits CYP3A, and its half-lives can be extended by 26-60% with repeated administration compared to single administration. Plasma concentration is weakly dependent on ITZ dose (likely due to saturation of formation process), influenced by serum albumin and GFR. Antifungal activity should consider both ITZ and Hydroxy Itraconazole plasma concentrations, with similar pharmacokinetics to ITZ in immunocompromised patients on ITZ oral solution.
