ArticlesKetobemidone May Alter Busulfan Pharmacokinetics During High-Dose TherapyHassan, Moustapha*† ; Svensson, Jan-Olof† ; Nilsson, Christína*† ; Hentschke, Patrik‡§ ; AL-Shurbaji, Ayman† ; Aschan, Johan*§ ; Ljungman, Per*; Ringdén, Olle‡§Author Information *Department of Medicine, Division of Hematology; †Department of Medical laboratory sciences & technology, Division of Clinical Pharmacology; ‡Center for Allogeneic Stem Cell Transplantation; §Division of Clinical Immunology, Huddinge University Hospital, Huddinge, Sweden Received August 31, 1999; accepted January 31, 2000. Address correspondence and reprint requests to Dr. Moustapha Hassan, Laboratory of Hematology, KFC, Novum, Huddinge University Hospital, 141 86 Stockholm, Sweden Therapeutic Drug Monitoring: August 2000 - Volume 22 - Issue 4 - p 383-385 Buy Abstract The authors report a possible interaction between ketobemidone and busulfan during myeloablative treatment of a patient with acute myeloid leukemia. At the time of admission, the patient was receiving ketobemidone 1,000 mg/d as analgesic for a rectal fissure. The patient started conditioning prior to bone marrow transplantation with busulfan (1 mg/kg × 4 for 4 days). High busulfan plasma concentrations were observed after the first dose and the next doses were reduced to 0.7 mg/kg. The kinetics of both drugs revealed that an increase in ketobemidone concentration was followed by an increase in busulfan levels. Substituting ketobemidone with morphine resulted in a decrease in busulfan concentration despite increasing the dose once more to 1 mg/kg. © 2000 Lippincott Williams & Wilkins, Inc.