Tacrolimus-Associated Adverse Effects After Liver Transplantation: A Narrative Review

Background: Tacrolimus is currently the most commonly used immunosuppressive agent after liver transplantation, administered to prevent allograft rejection, but it is also associated with numerous adverse effects. Purpose: The aim of this review was to summarize the most clinically relevant and well-documented adverse effects of tacrolimus after liver transplantation, focusing on their mechanisms, clinical presentation, approximate incidence, and overall clinical significance. Methods: We searched the PubMed and Medline databases and included articles, randomized controlled trials, cohort studies, review articles, and case reports published between 2016 and 2026. Results: The most common causes of morbidity in the early days following liver transplantation and initiation of tacrolimus therapy are acute nephrotoxicity, systemic infections, and signs of neurotoxicity. In the majority of patients, these manifestations resolved after dose reduction or complete discontinuation of the drug. During the early post-transplant period, opportunistic infections were the main cause of morbidity, with bacteria being the most frequent pathogens, while mortality in certain fungal infections reached up to 50%. While acute toxicities are primarily influenced by drug dose, long-term use of tacrolimus, regardless of dose, can lead to the development of malignancies, metabolic disorders, cardiovascular diseases, and chronic kidney disease, with incidence estimates varying widely. Conclusions: Consistent monitoring of patients on tacrolimus is crucial to ensure maximum therapeutic benefit and to reduce the risk of associated adverse effects.