Drug Interaction Between Tacrolimus and Paxlovid (Nirmatrelvir/Ritonavir) in an Adolescent with Inflammatory Bowel Disease.

Abstract

The coronavirus disease of 2019 (COVID-19) led to a worldwide pandemic. The emergency use of a combination of nirmatrelvir/ritonavir (paxlovid) was approved for high-risk individuals (such as immunocompromised) testing positive for the disease. We present a patient with ulcerative colitis being treated with tacrolimus, as well as ustekinumab, who was diagnosed with COVID-19 and placed on paxlovid due to her immunosuppressed state. She stopped her tacrolimus while on paxlovid and did well clinically. Tacrolimus was restarted 12 hours after completion of paxlovid, but she became symptomatic with vomiting, headache, and malaise and was found to have a toxic tacrolimus level. Tacrolimus was stopped and symptoms resolved, but levels remained elevated for a prolonged period. There is a paucity of literature on this drug-drug interaction, and with the resurgence of COVID-19, it is important to be cognizant of the potential for adverse effects and toxicity.