Effects of Triazole Antifungal Agents on the Plasma Concentration and Dosage of Cyclosporin in Patients with Aplastic Anaemia

Objectives. This study aimed to investigate the effects of different triazole antifungal agents on the blood concentration and dosage of cyclosporine (CsA) in patients with aplastic anaemia (AA). Methods. This retrospective study enrolled AA patients who received CsA and triazole antifungal agents simultaneously between January 2018 and December 2022. The ratio of CsA blood concentration (ng/mL) to dosage (mg/day) (C/D) co-administration with and without azoles was compared. The effects of different triazole antifungal agents on blood concentrations and dosages of CsA were analysed. Results. The mean C/D ratio of CsA increased 1.97 times when co-administered with posaconazole (POS), while the mean C/D ratio of CsA increased 1.76 times when co-administered with fluconazole (FCZ). Compared with CsA monotherapy, there was a significant difference in CsA concentrations among patients with azoles (P < 0.05). The mean dose of CsA decreased was 0.26 (−0.25—1.05) mg/kg/day and 0.18 (−0.50—0.69) mg/kg/day when co-administered with POS and FCZ, respectively. There is a wide interindividual variability in the magnitude of drug interaction between azoles and CsA. Conclusions. Although azoles increased CsA concentration, a wide individual variability was found in the patients with CsA C/D ratio. Therefore, the CsA dose should be adjusted by closely monitoring the blood levels of CsA co-administered with triazole antifungal agents. In addition, we observed that POS had a greater effect on the blood concentration of CsA than FCZ. When adjusting the dose of CsA in clinical practice, the blood concentration of CsA and the type of co-administered triazole antifungal agents should be considered.