BACKGROUND: Once-daily extended-release tacrolimus (Tac-OD) has been introduced as a useful therapeutic option to increase patient adherence to immunosuppressive therapy. This study aimed to evaluate the safety, efficacy and immunosuppressant adherence of conversion from twice-daily tacrolimus (Tac-BID) to Tac-OD in stable adult living donor liver transplant (LDLT) recipients in a single institution. 
METHODS: Between February and May 2013, Tac-BID was converted to Tac-OD in recipients followed up for at least 12 months after transplantation and without previous rejection episodes. The switching policy was based on a dose ratio of 1:1 with dose adjustment target trough levels at 3-5 ng/mL. Tacrolimus trough levels, laboratory parameters, metabolic disorders, and adverse events were assessed. 
RESULTS: A total of 229 patients were enrolled in the study. The median age at conversion was 53 years (range 31-73). The median transplant duration was 35.3 months (range 12.0-95.4). During a median follow-up of 13.5 months after conversion, 9 patients returned to Tac-BID because of adverse events. No acute rejection episodes were observed. Of 214 patients still on Tac-OD at 12 months, 12 (5.6%) received a reduced dose and 95 (44.4%) required an increased dose over baseline. Overall adherence was 82.2% at the end of follow-up. 
CONCLUSION: The conversion from Tac-BID to Tac-OD with similar target trough levels after conversion is safe and effective for long-term stable LDLT patients.