HIV 101: Treating HIV with Antiretroviral Therapy

By Chelsea Bailey | September 26, 2013

Tatu Msangi explains antiretroviral (ARV) medication to a client at a HIV care and treatment clinic in Tanzania.

James Pursey/EGPAF

In our previous installment of the HIV 101 series, we discussed the stages of HIV Infection. Today, we will dig deeper into the mechanics of how antiretroviral therapy (ART) reduces the amount of HIV present in the body and helps an HIV-positive patient stay healthy.

What is Antiretroviral Therapy

EGPAF has started more than 1 million individuals – including 95,000 children – on lifesaving antiretroviral therapy (ART).  ART refers to the drug treatment (typically combinations of drugs) used to suppress the viral load -- or the amount of HIV present in the body – and halt the progression of the disease.

ART uses separate classes of drugs to target the individual stages of the HIV lifecycle and to prevent them from occurring. These drugs work in concert to suppress the virus. Here’s how: 

Reverse Transcriptase (RT) Inhibitors

The first anti-HIV drugs developed were RT inhibitors.  In order for a human cell to become infected with HIV, the virus’ RNA (or genetic code) has to be converted into DNA. This process is called reverse transcription. The enzyme responsible for carrying out this conversion, reverse transcriptase, or RT, can be inhibited by these drugs to interrupt this critical step in the lifecycle of HIV.

Protease Inhibitors

HIV is a retrovirus, a type of infection that replicates by inserting its infected genetic blueprint into a host cell. Protease inhibitor drugs block the enzyme responsible for virus maturation and prevent the infected cell from making viruses which are infectious. They are among the most powerful class of HIV drugs. 

Integrase Inhibitors

These drugs block the integrase enzyme that HIV uses to insert its genetic code into the target host cell.

Entry and Fusion Inhibitors

Unlike the other classes ART drugs, which interrupt replication after HIV has infected the healthy immune cell, entry and fusion inhibitors block HIV at the first stage of the lifecycle, entry, which makes them unique.

Entry and fusion inhibitors work by attaching themselves to the proteins on the surface of HIV and CD4 cells to prevent the virus from being able to bind with and thereby infect new cells.

Combination Drug Therapy

Today, many HIV-positive patients take a single pill that combines the effects of multiple classes of drugs. This combination drug therapy is extremely potent and also helps prevent the virus from becoming resistant to drug treatment (because developing resistance to multiple drugs is much harder than developing resistance against only one).

The WHO now recommends combination drug therapy for all pregnant and breastfeeding women.

To learn more about how ARVS work, read this article from the National Institute of Health on treating HIV and AIDS.

Chelsea Bailey is Communications Assistant for the Foundation, based in Washington, D.C.