[Are all analogue combinations equal?].

The huge improvement in the therapeutic arsenal for HIV infection has led to HIV becoming a chronic disease. Like us, our patients are aging and their life expectancy is close to that of the general population. Consequently, we need safe, easily administered drugs with interactions that can be controlled and the least possible impact on highly prevalent comorbidities such as atherosclerosis or coinfection with hepatotropic viruses. Drugs should fit the patient's lifestyle without affecting quality of life and, above all, be free of effects leading to stigma, such as lipoatrophy, a major concern for most recently diagnosed patients. The choice of the two nucleoside analogue reverse transcriptase inhibitors used at the start of antiretroviral therapy should be based on careful evaluation of the abundant data accumulated on all these determining factors which are heralding a new era in the control of HIV infection. Thus, in this scenario, thymidine analogues have been relegated to alternative use. Fixeddose combinations of tenofovir and emtricitabine (TDF/FTC) or abacavir and lamivudine (ABC/3TC) are the backbone of choice when initiating antiretroviral therapy. Direct comparative data are still scarce but suggest similar virological efficacy, with highly preliminary data suggesting some disadvantages associated with the use of ABC/3TC. After excluding patients at risk of hypersensitivity to ABC, both combinations are well tolerated, but TDF/FTC is associated with a better lipid profile. Recent data from the Data Collection on Adverse Events of Anti-HIV drugs (DAD) study show an unexpected association of ABC with increased cardiovascular risk and thus more detailed studies are required.