Tacrolimus toxicity in organ transplantation: an overview

Abstract

Tacrolimus is a macrolide lactone antibiotic, and acts as a calcineurin inhibitor. It is widely used to prevent organ transplant rejection. It has been approved as first-line treatment after organ transplantation. Tacrolimus has narrow therapeutic range and wide individual variability in its pharmacokinetics. In organ transplantation, immunosuppression is associated with important risks, in particular, related to infections and cardiovascular diseases, which are the predominant causes of death in those with a functioning graft. This review focuses on toxicity of tacrolimus after transplantation. Tacrolimus toxicity is a major determinant of morbidity and mortality in organ recipients after transplantation. Therefore, reducing toxicities has become a priority. To decrease the incidence of side effects, and expand graft survival, the appropriate initial and maintenance dose of tacrolimus is essential. Clinical conditions that influence tacrolimus pharmacokinetics, such as hemorrhage, systemic inflammation and shock, all result in higher variations of tacrolimus concentrations. In addition, unbound plasma concentration is a major important reasonable parameter for monitoring of receiving optimal tacrolimus dosing in the unstable patient. Therefore, the approach of tacrolimus monitoring is vital and will support to avoid tacrolimus toxicity in the early days after transplantation.