P2605 - Paxlovid-Induced Tacrolimus Toxicity in a Liver Transplant Patient

Sadia Aslam, MD, Sharma Neha, MD, Vura Naga Venkata Rama Krishna, MD
UTHSCSA, San Antonio, TX

Introduction: Paxlovid (nirmatrelvir/ritonavir) is FDA-approved for mild-to-moderate COVID-19 treatment. Ritonavir-mediated CYP3A inhibition is potentiated by immunosuppressive drugs, increasing the risk of adverse reactions. We present a case of Paxlovid-induced tacrolimus toxicity in a liver transplant patient, resulting in hypertensive urgency, abdominal pain, nausea, hyponatremia, hyperkalemia, and acute kidney injury. Treatment with phenytoin was successful.

Case Description/Methods: A 72-year-old female with cryptogenic cirrhosis status post orthotopic liver transplant and receiving tacrolimus (CNI) was treated for COVID-19 pneumonia with Paxlovid (nirmatrelvir/ritonavir). During a clinic visit, routine lab tests showed acute kidney injury, hyperkalemia, and hyponatremia. She was later admitted to the hospital with a four-day history of right upper quadrant abdominal pain and nausea. Her surgical history and review of systems were otherwise insignificant, and her social history was negative for smoking, active alcohol use, or illicit drug use.




She had elevated blood pressure of around 180/110 mmHg on admission. Vitals and physical exams were otherwise not significant. On laboratory analysis, serum creatinine of 2 mg/dL (baseline of 1.3 mg/dL), Sodium 129 mEq/L (baseline of 138 mEq/L), and Potassium of 5.6 mEq/L were present; complete blood count and chemistry panel were otherwise normal. She also had an elevated Prograf level of 206 ng/ml (the normal range is 4 - 16 ng/ml). Despite holding Tacrolimus, her levels stayed over 200 on day 2 of hospital admission. The patient was eventually started on Phenytoin to help with calcineurin inhibitor (CNI) metabolism. Her symptoms resolved and electrolytes came to normal range after starting the Phenytoin. Her Prograf level was 7.2 at the time of discharge. Subsequent outpatient Follow-up visits showed stable Prograf levels.

Discussion: Tacrolimus toxicity can cause various symptoms, and CNI nephrotoxicity is reversible. Paxlovid-induced tacrolimus toxicity in three case reports. Due to severe drug interactions, the COVID-19 Drug Interactions database warns against Paxlovid use with tacrolimus. The American Society of Transplantation recommends alternative therapy, and the National Institutes of Health suggests holding tacrolimus during Paxlovid treatment. Avoiding Paxlovid in people taking tacrolimus is crucial, if possible, due to the severe drug-to-drug interaction, as highlighted in our case.


Disclosures:


Sadia Aslam, MD, Sharma Neha, MD, Vura Naga Venkata Rama Krishna, MD. P2605 - Paxlovid-Induced Tacrolimus Toxicity in a Liver Transplant Patient, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.