Tacrolimus dosage requirements in living donor liver transplant recipients with small-for-size grafts

AIM: To investigate the tacrolimus dosage requirements and blood concentrations in adult-to-adult right lobe living donor liver transplantation (AALDLT) recipients with small-for-size (SFS) grafts. METHODS: During January 2007 and October 2008, a total of 54 cases of AALDLT with an observation period of 6 mo were enrolled in this study. The 54 patients were divided into two groups according to graft-recipient body weight ratio (GRBW): SFS grafts group (Group S, GRBW < 0.8%, n = 8) and non-SFS grafts group (Group N, GRBW >= 0.8%, n = 46). Tacrolimus 12-hour blood levels and doses were recorded during weeks 1, 2, 3 and 4 and months 2, 3, 4, 5 and 6 in group S and group N. Meanwhile, acute rejection rates, liver and renal function test results, and the number of potentially interacting medications were determined at each interval in the two groups. A comparison of tacrolimus dosage requirements and blood levels were made weekly in the first month post-surgery, and monthly from months 2 to 6. RESULTS: There were no differences in the demo-graphic characteristics, acute rejection rates, liver and renal function test results, or the number of potentially interacting medications administered between the two groups. The tacrolimus dosage requirements in group S were significantly lower than group N at 2 A (2.8 +/- 0.4 mg/d vs 3.6 +/- 0.7 mg/d, P = 0.006), 3 wk (2.9 +/- 0.7 mg/d vs 3.9 +/- 0.8 mg/d, P = 0.008), 4 wk (2.9 +/- 0.8 mg/d vs 3.9 +/- 1.0 mg/d, P = 0.023) and 2 mo (2.8 +/- 0.7 mg/d vs 3.8 +/- 1.1 mg/d, P = 0.033). Tacrolimus 12-h trough concentrations were similar between the two groups at all times except for 2 A post-transplantation, when the concentrations were significantly greater in group S recipients than in group N recipients (11.3 +/- 4.8 ng/m L vs 7.0 +/- 3.8 ng/m L, P = 0.026). CONCLUSION: SFS grafts recipients have significantly decreased tacrolimus dosage requirements compared with non-SFS grafts recipients in AALDLT during the first 2 mo post-surgery. (c) 2009 The WJG Press and Baishideng. All rights reserved.