Background Adefovir disoproxil (ADF) was the second nucleoside analogue to be approved for Hepatitis B Virus (HBV) treatment. Later studies showed that tenofovir had better and more cost effective clinical outcomes for HBV treatment.

Purpose To analyse the treatment changes in patients with chronic infection on ADF treatment. To define treatment changes and their clinical causes and effects in our population.

Materials and Methods A retrospective observational study was performed in a tertiary hospital including all patients treated with ADF between January 2005 and September 2012. Data collected: demographics (sex, age) previous treatment, ADF treatment duration, reasons for changing from ADF, new drug prescribed, HBV DNA viral load at the moment of change and 6 months later.

Results Fifty-nine patients started treatment with ADF during the study period; men (81.4%), mean age: 42 years. Previous treatment: 45 treatment-naïve, 2 Peginterferon-a2-a and 12 lamivudine. Fourteen patients were lost to follow-up. Of the 45 patients included mean duration of treatment with ADF was 44.96 months (range: 3–92). 40 patients changed treatment with ADF: 27 patients switched to TDF with undetectable HBV DNA viral load (two of them returned to ADF due to intolerance); 15 patients switched due to detectable HBV DNA-viral load: 10 patients to TDF and 5 to ETV. 5 patients remain on ADF.

Conclusions Nearly every patient treated with ADF has changed treatment at some point and are no longer treated with this drug.

Most patients switched from ADV to TDF without any clinical reason; this may be related to better clinical outcomes and cost effectiveness.

No conflict of interest.