{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T04:21:04Z","timestamp":1789791664401,"version":"4.0.1"},"reference-count":22,"publisher":"Oxford University Press (OUP)","issue":"13","license":[{"start":{"date-parts":[[2024,2,13]],"date-time":"2024-02-13T00:00:00Z","timestamp":1707782400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2024,6,24]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Purpose<\/jats:title>\n                  <jats:p>Nirmatrelvir\/ritonavir is one of few options for outpatient treatment of COVID-19, but its use has been limited in transplant recipients due to significant drug interactions with immunosuppressants. Tacrolimus toxicity is possible when the drug is coadministered with nirmatrelvir\/ritonavir and may require urgent reduction of tacrolimus levels. This case series describes the use of phenytoin for enzyme induction in 5 adult solid organ transplant recipients with supratherapeutic tacrolimus levels resulting from coadministration with nirmatrelvir\/ritonavir.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Summary<\/jats:title>\n                  <jats:p>Solid organ transplant recipients are at high risk for complications related to COVID-19. Outpatient treatment options are limited, and therapeutic drug monitoring is complex in patients requiring quarantine. The 5 solid organ transplant recipients described herein were initiated on nirmatrelvir\/ritonavir in the outpatient setting and subsequently presented with supratherapeutic tacrolimus concentrations greater than 59 ng\/mL and developed signs and symptoms of tacrolimus toxicity. In all patients, nirmatrelvir\/ritonavir and tacrolimus were discontinued, and oral phenytoin (200-400 mg\/day) was given for 2 to 4 days. Tacrolimus was resumed once tacrolimus levels decreased to appropriate levels.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>These observations demonstrate that metabolism induction using phenytoin may be a useful strategy in the setting of supratherapeutic tacrolimus levels resulting from concomitant administration with nirmatrelvir\/ritonavir.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/ajhp\/zxae032","type":"journal-article","created":{"date-parts":[[2024,2,13]],"date-time":"2024-02-13T07:11:07Z","timestamp":1707808267000},"page":"e345-e352","source":"Crossref","is-referenced-by-count":6,"title":["Phenytoin enzyme induction for management of supratherapeutic tacrolimus levels due to drug-drug interaction with nirmatrelvir\/ritonavir: Case series and discussion"],"prefix":"10.1093","volume":"81","author":[{"given":"Jennifer","family":"Marsh","sequence":"first","affiliation":[{"name":"University of South Florida Taneja College of Pharmacy , Tampa, FL , USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angela T","family":"Logan","sequence":"additional","affiliation":[{"name":"Tampa General Hospital , Tampa, FL , USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erin P","family":"Bilgili","sequence":"additional","affiliation":[{"name":"Tampa General Hospital , Tampa, FL , USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lyndsey J","family":"Bowman","sequence":"additional","affiliation":[{"name":"Tampa General Hospital , Tampa, FL , USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Allyssa R","family":"Webb","sequence":"additional","affiliation":[{"name":"Tampa General Hospital , Tampa, FL , 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