Clinical experience of conversion from twice-daily standard-release tacrolimus to once-daily prolonged-release tacrolimus in stable renal transplant recipients

Abstract

Background: Conversion of standard-release tacrolimus to prolonged-release once-daily tacrolimus is often performed in a 1:1 (mg:mg) manner. We sought to determine the safety and efficacy of this conversion strategy in Chinese renal transplant recipients. Methods: In this single-center study, 16 stable renal transplant recipients were observed for 1 year after a milligram to milligram switch from standard-release to prolonged-release tacrolimus formulation. Trough blood tacrolimus level and graft function were serially monitored. Results: Mean daily dose of tacrolimus was 0.040 ± 0.018 mg/kg before conversion. After conversion, we observed a significant decrease in trough tacrolimus levels, from 4.5 ± 2.2 ng/mL to 3.4 ± 1.1 ng/mL (p = 0.046) at 1 month, and from 4.5 ± 2.2 ng/mL to 3.3 ± 1.1 ng/mL (p = 0.01) at 12 months. After 12 months, 44% of patients (n = 7) experienced a decrease in tacrolimus blood levels of more than 20%. All patients maintained stable graft function otherwise, without acute rejection. Conclusion: Our findings confirm that trough tacrolimus blood level can decrease following a 1:1 (mg:mg) conversion from standard-release to prolonged-release tacrolimus formulation in Chinese patients. Close monitoring of the drug levels and clinical condition seems to be warranted after medication switch. © 2011, Hong Kong Society of Nephrology Ltd. Published by Elsevier Taiwan LLC. All rights reserved.