2021 Volume 58 Issue 2 Pages 160-165
We report a case for which phenytoin (PHT) was effective in decreasing tacrolimus (Tac) concentration in a 9-year-old girl diagnosed with acute myeloid leukemia. The patient received chemotherapy, but no remission could be achieved. Therefore, allogeneic hematopoietic stem cell transplantation was performed with myeloablative conditioning. Engraftment was achieved on day 20. She complained of right hypochondralgia, and a mild elevation of hepatobiliary enzymes was observed on day 33, which led to the diagnosis of hepatic sinusoidal obstruction syndrome. Despite withholding Tac administration on day 38, its concentration increased to 34.6 ng/mL on day 40. Since Tac could not be removed by dialysis, PHT was administered with the hope of decreasing the Tac concentration via its interaction with PHT. The Tac concentration was 18.4 ng/mL on the day after PHT administration was initiated, and it decreased steadily thereafter. PHT may be an effective option for elevated Tac levels.
