Abstract
Fosravuconazole-induced renal dysfunction is rare. We measured serum creatinine (s-Cr) levels every 4 weeks in 30 sample sets from 30 patients who received fosravuconazole over 12 weeks for onychomycosis between June 2020 and March 2022 at our clinic. Compared with levels at oral therapy initiation, s-Cr levels increased in all patients at 4 weeks, in all except one patient at 8 weeks, and in all except three patients at 12 weeks; however, all levels were significantly higher than those at therapy initiation (p<0.001). The change in s-Cr levels showed a mean increase of 0.1 mg/dL after 4 weeks, and levels remained elevated at 8 and 12 weeks. On the other hand, the estimated glomerular filtration rate (eGFR) showed a mean decrease of 8.4 mL/min/1.73 m2 at 4 weeks. Renal function was evaluated using cystatin C (Cys) in only one patient, who showed a decrease in Cys-based eGFR as well as Cr-based eGFR. We observed no correlation between the 4-week change or the rate of eGFR and age and sex. However, only the change in eGFR at 4 weeks was significantly negatively correlated with renal function at the time of therapy initiation (p<0.005). The eGFR at commencement of the additional medication administration improved significantly compared with that at the end of the first therapeutic course in five patients who received additional medication after completion of the first course without treatment (p<0.005). Furthermore, eGFR at commencement of additional administration improved to eGFR at the commencement of the first medication course. Although the detailed mechanism remains unknown, considering that the eGFR recovered without treatment upon completion of oral administration, fosravuconazole-induced renal dysfunction may be a transient and reversible change. Even if the s-Cr level increased after initiation of fosravuconazole therapy, 12-week treatment appears safe and feasible with careful monitoring.
