Grand RoundsA Patient With Sepsis-Induced Multiorgan Failure and Increasing Serum Methadone Concentration: A Case StudyDale, Gro Helen MD, PhD*; Holmaas, Gunhild MD†; Berg, Jon A. MD*,‡; Riedel, Bettina MD, PhD*,‡; Schjøtt, Jan MD, PhD*,‡,§; Bjånes, Tormod K. MD, PhD* Author Information Departments of *Medical Biochemistry and Pharmacology and †Anesthesia and Intensive Care, Haukeland University Hospital; ‡Department of Clinical Science, Faculty of Medicine and Dentistry, University of Bergen; and §Regional Medicines Information and Pharmacovigilance Centre (RELIS Vest), Haukeland University Hospital, Bergen, Norway. Correspondence: Gro Helen Dale, MD, PhD, Jonas Lies Vei 65, 5021 Bergen, Norway (e-mail: [email protected]). The authors declare no conflict of interest. Therapeutic Drug Monitoring: June 2022 - Volume 44 - Issue 3 - p 366-368 doi: 10.1097/FTD.0000000000000963 Buy Metrics Abstract The authors describe a patient with substance use disorder admitted to the hospital with septic shock and multiorgan failure, in whom the serum concentration of methadone kept increasing despite discontinuation of the drug. Therapeutic drug monitoring was performed to monitor the methadone serum concentration during treatment of the underlying diseases. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.