Influence of CYP2C19*2/*17 genotype on adverse drug reactions of voriconazole in patients after allo-HSCT: a four-case report

Purpose Voriconazole (VCZ) is a new-generation triazol antifungal agent. CYP2C19 mutations have been reported to cause variability in VCZ pharmacokinetics, and thus lead to undesirable effects of pharmacotherapy. We observed four Caucasian patients who underwent allogenic hematopoietic stem cell transplantation, treated with voriconazole for prevention of fungal infections, to establish the impact of CYP2C19*2/*17 genotype on side effect occurrence. Methods Genetic testing for CYP2C19 allele*2 and*17 was performed using two PCR-RFLP methods established by Goldstein and Blaisdell, and Sim et al. All four patients presented CYP2C19*2/*17 genotype. Results The patients suffered from gastrointestinal, dermatological, neurological, hepatobiliary and renal adverse drug reactions (ADR). ADR could be best described by the use of VCZ. Other drugs potentially causing side effects were also taken into consideration. The presented complications were temporary and did not force dosage regimen adjustments or discontinuation of pharmacotherapy. After 2 months, the patients were discharged from hospital. Conclusions Drug–drug interactions and ADR may occur even if an agent is used for prophylaxis only. We, therefore, should use any available tools for pharmacotherapy optimization—also genetic testing.