Background The introduction of newly-approved antiretroviral drugs is leading to changes in first-line antiretroviral prescription.

Purpose To analyse the evolution of antiretroviral prescription patterns over a 4-year period in treatment-naïve HIV-infected patients and to assess rates and reasons for switching first-line HAART.

Material and methods Retrospective study including all antiretroviral-naïve patients who started HAART in a Spanish tertiary care hospital between 2010 and 2013. Prescription and pharmacy repeat prescription data were collected from the electronic prescription database and medical records.

Results 156 antiretroviral-naïve patients were included. Tenofovir/emtricitabine co-formulation was used as first-line nucleoside reverse transcriptase inhibitors combination in all but two patients with decreased renal function, who received abacavir/lamivudine instead. Efavirenz was the most commonly associated third drug: 65.1%, 62.5%, 43.2% and 57.1% each year, respectively. Protease inhibitor (PI)-based HAART increased over the years, with darunavir/ritonavir (DRV/r) and atazanavir/ritonavir (ATV/r) replacing lopinavir/ritonavir (LPV/r) as preferred PI: DRV/r was chosen in 23.3%, 31.2%, 21.6% and 21.4% of prescriptions, respectively; ATV/r, first introduced in 2012, was used in 29.7% of prescriptions that year and in 10.7% in 2013. LPV/r use decreased from 7.0% in 2010 to 4.1% and 2.7% in 2011 and 2012, respectively. There were only three prescriptions for raltegravir due to resistance or interaction issues, and one prescription for tenofovir/emtricitabine/rilpivirine, first introduced in late 2013. Treatment changes were necessary in 47 patients, and the main reasons for switching were: adverse events (55.3%), virological failure (14.8%), simplification (12.7%), interactions (10.6%), immunological failure (4.2%) and resistance mutations (2.1%).

Conclusion Antiretroviral prescription patterns in first-line HAART have widened in recent years due to the introduction of new agents, and adverse events remain the major reason for switching first-line treatment. With new drugs approved in 2014, practice protocols should be developed and implemented with pharmacist collaboration, in order to optimise clinical outcomes and financial impact of this changes.

References and/or acknowledgements No conflict of interest.