Antiretroviral therapy (ART) is the primary treatment for human immunodeficiency virus (HIV). It involves using a combination of medicines to reduce the amount of HIV in the body, protect immune system function, and prevent the progression of HIV infection. Different medication classes target specific stages of the virus life cycle.
HIV affects the immune system by targeting CD4 cells, which help the body fight infections. Without effective treatment, the virus can gradually weaken immune defenses and increase the risk of serious illnesses. Antiretroviral therapy works by interfering with HIV replication, allowing the immune system to recover or maintain its function. Although ART does not currently eliminate HIV from the body, it can suppress the virus to very low levels. Treatment selection depends on individual health circumstances, potential drug interactions, resistance testing, and clinical recommendations.
Antiretroviral therapy uses medicines that target different stages of the HIV life cycle. Combining medications with complementary mechanisms helps suppress viral replication and reduces the likelihood of drug resistance. Treatment is generally recommended for everyone diagnosed with HIV, regardless of their CD4 cell count or the duration of infection.
The primary goal of ART is to achieve and maintain an undetectable viral load. When viral suppression is sustained, the immune system can function more effectively, and the risk of HIV-related complications decreases. People who maintain an undetectable viral load through treatment do not sexually transmit HIV. This principle is commonly known as Undetectable Equals Untransmittable, or U=U.
Important aspects of antiretroviral therapy include:
Combination treatment: Most initial regimens combine medicines from at least two drug classes, commonly using an integrase strand transfer inhibitor with two nucleoside or nucleotide reverse transcriptase inhibitors.
Viral load monitoring: Blood tests measure the amount of HIV in the bloodstream and help determine whether treatment is working effectively.
CD4 cell monitoring: CD4 counts provide information about immune system health and the risk of certain infections.
Medication adherence: Taking medicines according to the prescribed schedule helps maintain viral suppression and lowers the risk of resistance.
Ongoing medical care: Healthcare professionals review side effects, other medications, kidney and liver function, and any changes in treatment needs.
HIV medications are grouped according to the stages of viral replication they block. Each class acts on a particular viral process, and understanding these differences explains why treatment commonly combines several medicines.
The major antiretroviral medication classes include:
Nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs): Medicines such as tenofovir and emtricitabine interfere with reverse transcriptase, an enzyme HIV uses to convert its RNA into DNA.
Non-nucleoside reverse transcriptase inhibitors (NNRTIs): Medicines such as doravirine and rilpivirine inhibit reverse transcriptase through a different mechanism, reducing the virus's ability to reproduce.
Integrase strand transfer inhibitors (INSTIs): Medicines such as dolutegravir and bictegravir prevent HIV DNA from integrating into the DNA of human immune cells.
Protease inhibitors (PIs): Medicines such as darunavir block the HIV protease enzyme, preventing the production of mature, infectious viral particles. Some regimens use a boosting agent to increase drug levels.
Entry and attachment inhibitors: Medicines in this group interfere with HIV's ability to attach to or enter target cells. Examples include maraviroc, fostemsavir, and enfuvirtide, which act through different mechanisms.
Capsid inhibitors: Lenacapavir targets the HIV capsid, a protein structure involved in several stages of the viral life cycle. It is used in specific treatment circumstances.
The appropriate medication combination varies from person to person. Factors such as previous treatment, HIV drug resistance, pregnancy considerations, other medical conditions, and drug interactions can influence selection. Some medicines are available in single-tablet combinations, while others require separate doses or injections at specific intervals.
Antiretroviral therapy requires ongoing clinical supervision. People should not stop, change, or skip prescribed HIV medicines without consulting their healthcare professional. If side effects or difficulties with adherence occur, a clinician can assess the problem and discuss suitable alternatives. Regular monitoring helps maintain treatment effectiveness, support immune health, and reduce the risk of complications associated with HIV.