The Pharmacokinetic Characteristics of Methylprednisolone in Korean Renal Transplant Recipients

Ahn, Jong Hoon; Kahng, Kyoung Won; Kang, Ju Seop; Shin, In Chul; Kang, Chong Myung; Kwak, Jin Young

Abstract

Glucocorticoids are usually given according to a standard dosing protocol regardless of individual difference. We evaluated the pharmacokinetic characteristics of methylprednisolone and the degree of interpatient variation in stable Korean renal transplant recipients during the period of 15-21 days after transplantation. This study included 23 renal transplant recipients, 13 males and 10 females, who received kidneys from living donors with stable graft function and without episode of acute rejection. On the study day at 8 A.M., 16.3mg of ethylprednisolone sodium succinate (i.v.) was administered to each patient instead of usual dose (20mg) of prednisolone (p.o.) after sampling of 7cc of baseline blood and additional blood samples were drawn after starting infusion. Plasma was separated and analyzed for methylprednisolone level using high performance liquid chromatography (HPLC) assay, and parameters for pharmacokinetics were calculated. There was significant interpatient variation in the pharmacokinetics of methylprednisolone in our patients group. There was no significant difference in the pharmacokinetic parameters between patients with and without side effects of steroid. Korean renal transplant recipients had higher volume of distribution than black renal transplant recipients; lower clearance than white renal transplant recipients; longer t1/2 than both black and white renal transplant recipients. Even if the number of patients included in this study was too small to reach conclusion, the differences in the pharmacokinetics of glucocorticoids do not seem to be a significant risk factor for side effects of steroid after transplantation. It may be necessary to individualize the dose of a glucocorticoid to achieve an optimal effect and also we need to establish a new steroid regimen protocol for Korean renal transplant recipients.