Tacrolimus Concentration Fluctuations Caused by Chyle Leakage After Liver Transplantation: A Case Report

Background: Chyle leakage is known to be a rare postoperative complication following liver transplantation (LT), and continuous leakage of large volumes of chyle can worsen prognosis. However, its mechanism is not fully understood, and no existing reports show the influence of chyle leakage after LT on blood concentration of the drug tacrolimus. Case presentation: A 43-year-old male with primary hepatocellular carcinoma (HCC), decompensated cirrhosis, and massive ascites underwent orthotopic liver transplantation (OLT). During active chyle leakage, his daily tacrolimus dose was escalated to 4.0 mg with concurrent administration of a CYP3A5 inhibitor, but blood concentrations remained subtherapeutic (1.7–2.5 ng/mL). Conservative treatments failed, so intraperitoneal injection of erythromycin (0.75 g) dissolved in 25% glucose solution (40 mL) was initiated on postoperative day (POD) 11, then administered every other day. After three treatments, chylous drainage reduced significantly, and tacrolimus concentrations abruptly increased to 14.7 ng/mL following a marked reduction in chylous drainage (to 800 mL/d on POD 13). Subsequent dose adjustments stabilized tacrolimus levels at 4.6–6.2 ng/mL with a daily dose of 2.0 mg. Conclusions: Intraperitoneal injection of erythromycin hypertonic solution may promote lymphatic fistula closure via chemical stimulation, though its efficacy requires further validation. Chyle leakage likely reduces tacrolimus blood concentration through multiple potential mechanisms. This case highlights the need for clinical attention to the association between chyle leakage and immunosuppressant concentrations, though further studies are required for validation.