CASE REPORT article
Front. Antibiot.
Sec. Antibiotics in Clinical Settings
Volume 4 - 2025 | doi: 10.3389/frabi.2025.1705987
A case report of drug-drug interaction between voriconazole and simnotrelvir/ritonavir
Provisionally accepted
Tingting Chen*
Qingquan Zhang- Fujian Medical University Affiliated First Quanzhou Hospital, Quanzhou, China
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Co-administration of simnotrelvir/ritonavir with voriconazole should be avoided, as stated in the product insert of simnotrelvir/ritonavir, due to the anticipated decrease in voriconazole's plasma concentration. Currently, there are no published reports regarding a pharmacokinetic interaction between simnotrelvir/ritonavir and voriconazole. We present the case of an 88-year-old male with pulmonary aspergillosis and COVID-19 coinfection treated concurrently with voriconazole and simnotrelvir/ritonavir. Prior to initiating simnotrelvir/ritonavir, two trough concentrations of voriconazole were measured, yielding values of 2.8 mg/L and 2.6 mg/L, respectively. Two days after co-administration with simnotrelvir/ritonavir, the voriconazole trough concentration rose to 6.0 mg/L. The voriconazole dose was subsequently reduced by 25%, and simnotrelvir/ritonavir was discontinued after the completion of the standard 5-day course. One week after voriconazole dose reduction (four days after simnotrelvir/ritonavir withdrawl), the trough concentration was measured again and found to be 3.5 mg/L. This case indicates that the trough concentration of voriconazole increased significantly during co-administration with simnotrelvir/ritonavir. Moreover, the interaction persisted even after discontinuation of simnotrelvir/ritonavir, necessitating dynamic dose adjustments guided by therapeutic drug monitoring.
Keywords: Voriconazole, simnotrelvir/ritonavir, Drug-drug interation, Therapeutic drugmonitoring, COVID-19
Received: 15 Sep 2025; Accepted: 22 Oct 2025.
Copyright: © 2025 Chen and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Tingting Chen, ctt21012@163.com
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