The drug-drug interaction between Paxlovid and tacrolimus has been shown to be robust and noteworthy, leading to high risk of adverse events and acute kidney injury among patients with inflammatory bowel disease (IBD), Leenoy Zaarur pointed out during her poster presentation at the Crohn’s and Colitis Congress 2023 in Denver, Colorado.

By presenting a case study about a 13-year old girl with ulcerative colitis (UC) who tested positive for COVID-19, Zaarur demonstrated the importance of “not only ceasing tacrolimus when administering Paxlovid, but continuing discontinuation for a longer period post-completion of therapy to minimize interactions.”

Zaarur works with the pediatric gastroenterology department at the Phoenix Children's Hospital in Phoenix, Arizona.

The patient’s treatment progress with the combination of tacrolimus and Paxlovid showed toxic levels of tacrolimus of more than 60 ng/ml when the drugs were used in conjunction. Even though the electrolytes and creatinine were normal, the patient had to be admitted into the emergency room for vomiting, fatigue, headaches, and myalgia. Upon withholding tacrolimus for 48 hours, the symptoms resolved and the immediate levels were 15.8 ng/mL. After 3 days, these levels were 2.9 ng/mL.

Generally an immunosuppressant, tacrolimus has proved efficient in the management of organ transplants. However, it does require close monitoring as toxicity may lead to acute or chronic kidney disease. “The normal concentration is between 5-15 ng/mL,” Zaarur said.

With the uptick in COVID-19 cases, a large number of patients have been treated Paxlovid—a medication that was approved for use among patients 12 and older who tested positive for COVID-19 and are at high risk for severe infection. However, the use of Paxlovid and tacrolimus among patients with IBD could present its own set of challenges.

“If Paxlovid is to be used, we recommend reduction of daily tacrolimus dose during treatment and additionally early and frequent monitoring of both whole blood tacrolimus levels and serum creatinine so that adjustments may be made if needed to prevent complications,” Zaarur noted.

—Priyam Vora

Reference:
Zaarur L, Patel A and Pasternak B. Presentation number: P022. Drug interaction between paxlovid and tacrolimus in an adolescent with inflammatory bowel disease. Presented at: Crohn’s and Colitis Congress 2023; Janu