Korean J Transplant.  2022 Nov;36(Supple 1):S57. 10.4285/ATW2022.F-1755.

Acute kidney injury in kidney transplant recipients with active SARS-CoV-2 infection due to drug interaction of tacrolimus and nirmatrelvir/ritonavir: three serial case reports

• Park H
• Ko EJ
• Chung BH
• Yang CW

• KMID: 2535261
• DOI: http://doi.org/10.4285/ATW2022.F-1755

Abstract

The mortality of SARS-CoV-2 infection of kidney transplant recipients (KTR) is higher than that of general population since immu-nocompromised condition. A novel oral protease inhibitor against SARS-CoV-2, nirmatrelvir (NR) is considered as a good option for outpatient-based antiviral treatment by reducing the risk of hospitalization and death. However, NR is metabolized mainly by cytochrome P450 3A4 (CYP3A4), which also metabolize calcineurin inhibitor (CNI). Hence, co-administration of these two drug
results
in drug interaction and increases serum tacrolimus (TAC) level almost 50 times, inducing acute CNI toxicity. Here we report serial three cases, two cases of NR without CNI dose reduction and one case of NR with cessation of CNI after telemedicine consultation with transplant physician. In case 1, since the patient did not aware of the risk of co-administration of NR and TAC, he took these two drugs together, which lead to acute kidney injury due to CNI toxicity. After discontinuation of TAC, renal function was recovered soon with normalized serum TAC concentration. Contrastively, in case 2, 3 days of simultaneous admin-istration of NR and TAC led to sustained acute kidney injury even after discontinuation of TAC. Active intravenous hydration with cessation of TAC for several days improved renal function. However, in case 3, patient was informed to stop TAC with NR initia-tion in telemedicine consult, which resulted in harmless to renal function with stables serum TAC concentration nor any rejection event after 5 days of cessation of TAC. Therefore, special situation like SARS-CoV-2 pandemic, educating transplant recipient to discuss their new medication trough telemedicine with transplant specialist is very important to avoid acute graft injury.