Abstract:
An adequate level of tacrolimus in serum should be obtained to prevent acute rejection following
liver transplantation. Because of good gastrointestinal absorption of oral tacrolimus, adequate
trough levels can be achieved even in patients with short bowel syndrome. Rarely, adequate
through levels cannot be obtained by oral administration of the drug for several reasons such
as inadequate absorption, having a discordant patient, laboratory error, and/or interactions with
other drugs and foods. Here, we described a 16-year-old patient who had undergone massive
intestinal resection due to mesenteric torsion 5 years previously and required liver transplantation
for cryptogenic cirrhosis. Her remnant small bowel length was 90 cm. After a successful
living donor liver transplantation, oral tacrolimus administration resulted in inadequate through
levels in some parts of the postoperative period. We checked up all the potential reasons but
could not identify any cause. An intravenous tacrolimus including immunosuppressive regimen
was temporarily required. She maintained adequate blood levels of tacrolimus by parenteral
route for a while; thereafter, oral administration resulted in enough blood drug levels. She was
discharged with oral tacrolimus therapy. We concluded that very rarely, adequate blood levels
of tacrolimus cannot be achieved by oral administration for unexplained reasons. In such cases,
temporary administration of parenteral tacrolimus can be life-saving.
