Change in oral absorption of tacrolimus in a liver transplant recipient after reversal of jejunoileal bypass: Case report

Introduction. Jejunoileal bypass (JIB) was, at one time, a popular surgical technique for the treatment of morbid obesity. However, this operation was also associated with major complications. Consequently, many such procedures were eventually reversed. One of the most serious of these complications was liver failure. For those patients who developed cirrhosis, liver transplantation was one therapeutic alternative. Tacrolimus is one of the primary immunosuppressive agents used in liver transplantation. It is effective to prevent acute rejection episodes, but shows a narrow therapeutic index and can cause nephrotoxicity and neurotoxicity. This report describes the change in tacrolimus absorption that was observed after JIB reversal in a 57-year-old female liver transplant recipient. Results. Prior to JIB reversal, the mean tacrolimus dose was 7 mg twice daily with a whole-blood tacrolimus concentration ranging from 5.2 to 6.4 ng/mL. There was no appreciable peak in tacrolimus concentration, and the area under the concentration-time curve (AUC) was 10.9 ng/mL/h. After reversal, the daily tacrolimus dose was decreased to 5 mg twice daily, with a now-discernable peak concentration at 3 hours postdose. Furthermore, the AUC increased 90% to 20.7 ng/mL/h. Conclusion. After JIB reversal, the patient showed higher systemic levels of tacrolimus and required lower steady-state doses. It is therefore imperative that such patients be monitored closely to avoid tacrolimus-related toxicity.