Increased tacrolimus levels during diarrhea

While it is well known that diarrhea results in decreased trough levels of cyclosporin A, experience with levels of tacrolimus (FK506) and diarrhea is limited. We have therefore measured the tacrolimus trough levels of four m ale and two female recipients of solid organs before, during, and after gas troenteritis. The average age of these six patients was 31 (1-60) years. Fo ur patients had received a kidney transplant, one patient had undergone sim ultaneous kidney-pancreas transplantation, and another patient had received a liver transplant. Rotavirus was identified in the feces specimen of a 1- year-old child that had undergone liver transplantation. All patients showe d an elevated tacrolimus trough level (peak 20-60 ng/ml) after onset of gas troenteritis. Under symptomatic therapy and adequate adjustment of tacrolim us dose, the gastroenteritis stopped and tacrolimus levels returned to the therapeutic range. We recommend that FK506 levels be carefully monitored du ring diarrhea in order to prevent intoxication.