The mainstay of HIV treatment is antiretroviral therapy, which involves taking some HIV medicines, i.e. antiretrovirals (ARV) lifelong. Other names for the treatment strategy are HAART (highly active antiretroviral therapy), cART (combination antiretroviral therapy) or simply cocktail treatment. An ART regimen often comprises 3 or more drugs from more than 2 classes. More recently a combination of 2 specific drugs has also been proven effective.
The main classes of ARV commonly used for HIV infection are: nucleoside reverse transcriptase inhibitor (NRTI), non-nucleoside reverse transcriptase inhibitor (NNRTI), protease inhibitor (PI) and integrase strand transfer inhibitor (INSTI). A less commonly used drug class is entry inhibitor (EI), which broadly includes CCR5 antagonist, fusion inhibitor and post-attachment inhibitor. Normally, a regimen is composed of a backbone of 2 NRTIs plus a "third compound" – which can be a PI, NNRTI or INSTI. EI is less commonly used but may be required for salvage if common regimens fail.
The aim of HIV treatment is to effectively suppress viral load. Within three to six months of taking ARV regimen, the viral load is expected to become undetectable. Undetectability is defined differently by the sensitivity of the machine used for viral load measurement. It normally means below 50 copies/ml.
