Kidney Week

Abstract: PUB225

Molnupiravir Safety in Tacrolimus-Treated Kidney and Pancreas Transplant Recipients: No Drug Interactions and Preserved Allograft Function in a Single-Center Study and Literature Review

Session Information

• Publication Only

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Prikis, Marios, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Marios Prikis, MD

• Haq, Kanza, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Kanza Haq, MD

• Vanvught, Jamie, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Jamie Vanvught, PharmD

• Patterson, Selena, University of Vermont The Robert Larner MD College of Medicine, Burlington, Vermont, United States

Selena Patterson, RN

Background

Solid organ transplant recipients receiving calcineurin inhibitors are at high risk for severe COVID-19. Nirmatrelvir/ritonavir (Paxlovid) causes clinically significant drug–drug interactions with tacrolimus via CYP3A4 inhibition, leading to toxic tacrolimus levels and acute kidney injury. Molnupiravir, which lacks CYP-mediated metabolism, may represent a safer outpatient alternative, though real-world transplant data remain limited.

Methods

We conducted a single-center retrospective cohort study of kidney and simultaneous pancreas–kidney transplant recipients on tacrolimus treated with molnupiravir (800 mg twice daily for 5 days) for COVID-19. Paired tacrolimus trough levels and serum creatinine were compared before and after treatment. AKI was defined by KDIGO criteria. Wilcoxon signed-rank testing was used for paired analysis.

Results

Sixty-one encounters (52 patients; 55 kidney, 6 SPK) were analyzed. Mean age was 55.0 years; 91.8% were vaccinated. Treatment began a mean of 1.3 days after symptom onset. Tacrolimus levels were unchanged (5.52 vs. 5.47 ng/mL; p = 0.941). Serum creatinine remained stable (1.39 vs. 1.40 mg/dL; p = 0.706). Five encounters met AKI criteria, all attributable to COVID-19 or other causes. No events were linked to molnupiravir. No adverse effects or deaths occurred. One patient required hospitalization.

Conclusion

Molnupiravir demonstrated excellent safety with no evidence of drug–drug interaction or graft dysfunction in tacrolimus-treated recipients. These findings support its use as first-line outpatient therapy in this population. Given known risks of Paxlovid coadministration, improving prescriber awareness is essential to prevent avoidable toxicity and preserve graft function. Findings reinforce need for education among primary care, emergency, and non-transplant clinicians in practice.

Funding

• Clinical Revenue Support