Oral absorption of tacrolimus in children with intestinal failure due to short or absent small bowel

We describe two children with intestinal failure due to short or absent small bowel who underwent isolated liver transplantation for liver disease related to parenteral nutrition. Both received reduced-size liver grafts whilst awaiting a suitable small bowel donor. Immunosuppressive therapy was based on oral tacrolimus and intravenous steroids. Therapeutic levels of tacrolimus were achieved at low dosage of 0.14-0.28 mg/kg per day. Median and mean blood tacrolimus levels were 9.9 and 13.7 ng/ml (range 4.9-42.3 ng/ml) in case 1 and 5.8 and 7.2 ng/ml (range 1-30 ng/ml) in case 2 before small bowel transplantation, respectively. Following small bowel transplantation, levels were 17.1 and 20.1 ng/ml (range 9.2-30 ng/ml), with oral doses of 0.54-1.35 mg/kg per day. Both children died of adenovirus pneumonia, with functioning grafts. Our experience demonstrates that effective levels of immunosuppression can be achieved by oral administration of tacrolimus in children with short or absent small bowel.