SHM Converge Scientific Abstract ePoster Gallery-Mixed Medication Mayhem: Case of Nirmatrelvir-Ritonavir Adverse Interaction With Tacrolimus

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This case report describes a 41-year-old woman with hypertension and end-stage renal disease status post deceased donor kidney transplant in 2018, maintained on tacrolimus and mycophenolate mofetil. Four days before presenting to the emergency department, she was diagnosed with symptomatic COVID-19 at urgent care and prescribed nirmatrelvir-ritonavir (Paxlovid), which she had taken for 4 of 5 days.<br /><br />She arrived with myalgias, presyncope, dizziness, and nausea, and was found to be hypotensive (systolic BP 70 mmHg) and tachycardic (120 bpm). Laboratory testing revealed acute kidney injury, with creatinine rising to 4.8 mg/dL from a baseline of about 1.6–1.76 mg/dL. She also had oliguria/anuria, with bladder scan showing only 60 mL of urine. Her tacrolimus level was markedly elevated at 60 ng/mL, suggesting drug toxicity. She was treated empirically for sepsis with broad-spectrum antibiotics, given aggressive IV fluids and a short course of hydrocortisone, and tacrolimus was held during admission. Her kidney function improved, and creatinine returned to baseline by discharge. She was restarted on her home tacrolimus dose with close nephrology follow-up.<br /><br />The poster emphasizes that nirmatrelvir-ritonavir is a strong CYP450/CYP3A4 inhibitor and can cause dangerous interactions with tacrolimus and other calcineurin inhibitors. In transplant patients, this interaction may lead to severe tacrolimus toxicity and acute kidney injury. The authors recommend heightened physician awareness, multidisciplinary management with transplant pharmacy and nephrology, and consideration of alternative COVID-19 therapies such as remdesivir, bebtelovimab, or molnupiravir when appropriate.

Asset Subtitle

Ritika Gadodia

Meta Tag

Author List Meghan Conelly, Nikita Chintapally, Ritika Gadodia

Category Clinical Vignettes

Concept Nirmatrelvir/Ritonavir

Concept Tacrolimus

Concept CYP3A4 Inhibition

Concept Tacrolimus Toxicity

Concept Acute Kidney Injury

Distinguished Finalist

Presenter Organization Medstar Washington Hospital Center

Presenting Author Ritika Gadodia

Track Adult

Keywords

tacrolimus toxicity

nirmatrelvir-ritonavir

Paxlovid

kidney transplant

acute kidney injury

CYP3A4 inhibitor

calcineurin inhibitor

COVID-19 treatment

drug interaction

renal transplant

Nirmatrelvir/Ritonavir

Tacrolimus

CYP3A4 Inhibition

Tacrolimus Toxicity

Acute Kidney Injury