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

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.

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 > or = 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.

There were no differences in the demographic 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 significantly 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).

SFS grafts recipients have significantly decreased tacrolimus dosage requirements compared with non-SFS grafts recipients in AALDLT during the first 2 mo post-surgery.