Effect of mycophenolate mofetil on hematological side effects incidence in renal transplant recipients

Mycophenolate mofetil (MMF), an immunosuppressant administered after solid organ transplantation, is generally well tolerated; however, it frequently causes hematological toxicity. In this study, we aimed to assess the relation between the pharmacokinetic parameters of MMF metabolites (mycophenolic acid [MPA] and 7-O-MPA glucuronide [MPAG]) and the adverse effects on the hematopoietic system in renal transplant recipients. The four-h pharmacokinetic profiles of MPA and MPAG were determined using the HPLC method for MMF-treated patients (n = 61) among 106 renal transplant recipients (during the late post-transplant period) participating in the study. Anemia was more frequently observed in the study group compared with the control group (30.7% vs. 20.0%) and although the difference was insignificant, plasma iron concentrations were significantly higher in patients treated with MMF (32.9 ± 9.4 μmol/L vs. 28.7 ± 9.4 μmol/L; p = 0.032). Iron supplementation was more frequently applied to patients with anemia (48.2%) compared with patients with hemoglobin within the norm (20.3%; p = 0.005). As all MPAG pharmacokinetic parameters correlated negatively with hemoglobin and hematocrit, and MPAG pharmacokinetic parameters were higher in patients with anemia, MPAG may be the predicting factor of MMF side effects. In renal transplant recipients, especially with deteriorated renal function, extensive iron supplementation may be ineffective as anemia was associated with declined renal function and was not caused by low iron concentration.