This study aimed to analyze the mycophenolic acid (MPA) blood concentration in patients during the perioperative period after kidney transplantation and to observe the adverse reactions to MPA to promote rational clinical medication.

The clinical data of perioperative recipients after kidney transplantation at the First Affiliated Hospital of Zhejiang University School of Medicine from October 1 to November 31, 2022 were retrospectively analyzed. MPA- concentration of 0 h (C₀) were monitored in fifty-two recipients beginning on the second day after the operation. The MPA-area under curve (AUC) was monitored for 29 recipients on the fourth day after the operation. Patient information about age, sex, MPA-C₀, MPA-AUC, white blood cell levels, incidence of diarrhea and rejection was collected through the hospital information system. Independent sample t-test was used for comparisons between two groups, and P<0.05 indicated a statistically significant difference.

The average MPA-C₀ in 52 kidney transplant recipients was (4.1±2.3) mg/L, with 24 (46.15%) ranging from 1.0 to 3.5 mg/L and 28 (53.85%) exceeding 3.5 mg/L. The average MPA-AUC of 29 recipients was (54±23) mg·h^-1·L^-1, including 14 patients (48.28%) receiving 30-60 mg·h^-1·L^-1, 5 patients (17.24%) receiving less than 30 mg·h^-1·L^-1, and 10 patients (34.48%) receiving more than 60 mg·h^-1·L^-1. The MPA-AUC of female recipients (n=9) was higher than that of male recipients (n=20), with values of (68±16) and (48±23) mg·h^-1·L^-1, respectively (t=-2.31, P<0.05). Among the 29 recipients for whom the MPA-AUC was monitored, 19 used mycophenolate mofetil (MMF), and 10 used enteric-coated mycophenolate sodium (EC-MPS). The AUC of MMF and EC-MPS were (53±26) and (57±15) mg·h^-1·L^-1, respectively, with no statistically significant difference (t=0.46, P >0.05). None of the recipients experienced any rejection reactions during the perioperative period. One (1.92%) of the recipients experienced granulocytopenia on the 21st day after kidney transplantation. Six (11.54%) of the recipients experienced diarrhea, and symptoms improved after reducing the dosage of MPA and symptomatic treatment with montmorillonite powder.

There was a significant difference in MPA exposure levels among recipients during the perioperative period after kidney transplantation, with nearly half of the recipients not meeting the guidelines. The incidence of adverse reactions to MPA was relatively low, and higher exposure to MPA was not related to adverse reactions in recipients.