Abacavir/lamivudine (ABC/3TC) and tenofovir/emtricitabine (TDF/FTC) are the most widely used nucleoside reverse transcriptase inhibitor (NRTI) associations in HAART. ABC has been initially considered as one of the most benign antiretroviral drugs due to a better metabolic profile than other nucleoside analogues, but since the D.A.D. study reported an association between the use of ABC and an increase in cardiovascular risk there has been controversy around this drug.