International journal of antimicrobial agents
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Int. J. Antimicrob. Agents · Feb 2016
Impact of CYP2C19 genetic polymorphisms on voriconazole dosing and exposure in adult patients with invasive fungal infections.
Voriconazole (VCZ) use is limited by its narrow therapeutic range and significant interpatient variability in exposure. This study aimed to assess (i) the impact of CYP2C19 genotype on VCZ exposure and (ii) the doses required to achieve the therapeutic range in adult patients with invasive fungal infections (IFIs). Therapeutic drug monitoring (TDM) of VCZ, based on trough concentration measurement, and CYP2C19 genotyping were used to guide VCZ dosing in Caucasian patients with IFIs. ⋯ Indices of exposure for CYP2C19*2 carriers were in line with the functional effect of this polymorphism compared with CYP2C19*1/*1 individuals, however comparisons of doses required to achieve target concentrations were not statistically different. The CYP2C19*17 allele predicted both VCZ exposure and dose required to achieve effective and non-toxic concentrations. CYP2C19 genotyping appears useful to guide VCZ initial dosing when coupled with TDM and to explain subtherapeutic concentrations frequently observed in clinical practice.