Not everyone who is HIV positive requires treatment.  The decision to start treatment is based on a number of factors including your CD4 count, your HIV Viral load and whether or not you have had any health problems so far that can be attributed to HIV infection. 

If you do start HIV therapy, this will almost certainly be in the form of a combination Regimen of 3 or more drugs.  This Combination therapy is sometimes referred to as 'HAART' (Highly Active Anti-Retroviral Therapy) or just 'ART' (Anti-Retroviral Therapy).  Giving HIV drugs in combination in this manner adds to the power of the regimen and also helps to prevent viral Resistance from developing.  This will in turn help to ensure that the medication provides complete and durable suppression of the HIV Virus - as long as your treatment Adherence is good. 

Detail

HIV drugs are generally classed according to the way they stop the virus from reproducing itself.  There are now six main types of drugs used to combat HIV:

• Nucleoside analogue reverse transcriptase inhibitors (NRTIs).  These target an HIV protein called 'reverse transcriptase'
• Non-nucleoside reverse transcriptase Inhibitors (NNRTIs).  These also target 'reverse transcriptase'
• Nucleotide analogue reverse transcriptase inhibitors (NtRTIs).  These also target 'reverse transcriptase'
• Protease Inhibitors (PIs).  These target the 'protease' protein
• Entry Inhibitors (these include 'fusion inhibitors' and 'CCR5 antagonists').  These target the point when HIV gets insude CD4 cells
• Integrase Inhibitors.  These are a new class of drugs that target the integrase protein. 

By combining drugs from these classes a number of effective and safe combination regimes can be constructed.  There is no single 'right' combination for everybody.  Some of the important things to consider when choosing the right regimen for you are discussed under choosing a combination.