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 wk (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 wk post-transplantation, when the concentrations were signifi cantly greater in group S recipients than in group N recipients (11.3±4.8 ng/mL vs 7.0±3.8 ng/mL, P=0.026).CONCLUSION: SFS grafts recipients have signifi cantly decreased tacrolimus dosage requirements compared with non-SFS grafts recipients in AALDLT during the first 2 mo post-surgery.