HIV drug resistance occurs when antiretroviral drugs lose their ability to block the reproduction of the HIV virus within the body. There are several factors which contribute to the accumulation of drug-resistance during antiretroviral therapy. They include:

• Poor treatment adherence (not taking medications as or when recommended).
• Poor absorption (this can happen as a result of not taking medication with food or when diarrhea and vomiting is experienced and drugs are expelled from the gut too quickly).

HIV is a retrovirus. Retroviruses use their RNA as a template for creating DNA when inside a human host cell. This is how retroviruses multiply.

Knowing that HIV is a retrovirus is important to understanding how HIV treatment works. HIV treatment works by preventing HIV from multiplying. It is able to block multiplication by interrupting different stages of the retrovirus multiplication process.

There are many different “classes” of antiretroviral therapy. Each “class” of HIV ART works to fight HIV infection by interrupting various stages of the HIV replication cycle. Some stop or slow down the process of HIV from replicating within the body, while other drugs work by helping the body to fix the damage HIV has done to the immune system. Other drugs work by helping the immune system to become stronger and more effective at warding off illness and infections.

Deciding on a combination of ART is something that an individual usually does in consultation with their doctor or other health care professionals. When deciding upon the most suitable combination for an individual, several factors are considered including but not limited to: viral load, CD4 count, previous treatments and experiences to those treatments, dosages and adherence particulars (how drugs should be taken).

Antiretroviral therapy (often called ‘ARV therapy’ or ‘ART’) is drug therapy that has been developed to disrupt the cycle of HIV replication. ARVs come in a variety of formulations designed to act at different stages of the HIV virus life-cycle. ART usually consists of a combination of three or four different drugs, which can delay HIV replication and immune system deterioration within the body. Administering ARVs in combination is called Highly Active Antiretroviral Therapy (HAART) which is often more casually referred to as a ‘drug cocktail’.

HIV treatment is the use of medications (antiretroviral therapies) which can help keep an HIV infected person healthy. Drug research and development is on-going. While current treatment can help people living with HIV at all stages of the disease, it cannot cure HIV infection. Individuals are unique, from their biology to their lifestyle, and therefore HIV treatment is complex and should be tailored to meet the needs of each individual.