Background There are currently five approved nucleos(t)ide analogues (NUCs) for the management of chronic hepatitis B (CHB): lamivudine, adefovir dipivoxil, telbivudine, entecavir, and tenofovir disoproxil fumarate.

Objective To determine the persistence rates among patients receiving NUCs for CHB at weeks 48, 96 and 144, compare them in these periods, and analyse the evolution of treatment persistence.

Methods We conducted a retrospective study that included patients with CHB who initiated antiviral therapy and were attended to by the pharmaceutical care office between January 2002 and December 2011. Patients included in a clinical trial or patients who did not collect their medication personally were excluded. There were two different analyses: a comparative analysis of the persistence rates in three periods (weeks 1–48, weeks 48–96, and weeks 96–144); and a Kaplan-Meier analysis to evaluate the evolution of persistence.

Results A total of 102 patients were included. Persistence rates were different in the three periods. They decreased during the course of the different periods, and the decline was more rapid between the first and second period. There were statistically significant differences in the non-persistence of the five drugs (p<0.005). Entecavir had the best profile of persistence, followed by tenofovir.

Conclusions This study showed that high genetic barrier drugs had a better profile of persistence in the initial treatment of patients with CHB. Data seem to suggest entecavir may offer better persistence rates than tenofovir, and the persistence rates for all five medications dropped in weeks 48–96.