How does antiretroviral therapy work? Principle of action, types of drugs and when to start treatment

How antiretroviral therapy works

Antiretroviral therapy treats HIV by suppressing the activity of the virus in the body. For most people who take antiretroviral drugs, they are very effective at controlling HIV.

Treatment helps improve quality of life and gives people with HIV the same life expectancy as healthy people.

Suppressing viral activity results in a low viral load and a reduced risk of developing other diseases. Therefore, the main goal of antiretroviral therapy is to reduce a person's viral load to an undetectable level, which eliminates the risk of transmitting the virus to other people.

HIV attacks the body's immune system. A weak immune system means that the body will not be able to fight various diseases: from infections to oncology . Antiretroviral drugs prevent HIV from multiplying, thereby protecting cells that might otherwise be affected by the virus.

The less HIV is present in a person's body, the easier it will be for the immune system to recover.

Types of antiretroviral drugs

Treatment for HIV involves a combination of medications. The table lists the different categories and names of antiretroviral drugs, as well as how they affect the body.

Group name	Operating principle	Drugs
Nucleoside reverse transcriptase (NRTIs)	Block the action of an enzyme called viral reverse transcriptase, which is necessary for HIV	Abacavir (Ziagen); Emtricitabine (Emtriva); Lamivudine; Stavudin (Zerit, Stavudin); Tenofovir (Viread); Zidovudine (Retrovir)
Nonnucleoside reverse transcriptase inhibitors (NNRTIs)	They work similarly to NRTIs. The only difference is that they act on different parts of the enzyme	Delavirdine; Doravirine); Efavirenz (Sustiva); Etravirine; Nevirapine (Viramune); Rilpivirine (Edurant)
Protease inhibitors (PIs)	Interferes with another viral enzyme, HIV protease. HIV requires proteases to replicate.	Atazanavir (Reyataz); Darunavir (Prezista); Fosamprenavir (Lexiva, Telzir); Indinavir (Crixivan); Lopinavir (Kaletra); Ritonavir (Norvir); Saquinavir (Invirase); Tipranavir (Aptivus)
Entry inhibitors	Prevents the virus from entering target cells. To enter immune cells, HIV must fuse with cell receptors, and these drugs work to prevent this from happening. People often take entry inhibitors when other treatments have failed	Enfuvirtide (Fuzeon); Maraviroc
Integrase inhibitors	HIV uses a protein called integrase to send its genetic material into the cells it targets. Integrase inhibitors block this action.	Dolutegravir (Tivicay); Elvitegravir (Vitecta); Raltegravir (Isentress)

Interaction with other substances and side effects of drugs

Antiretroviral drugs may interact with other medications, supplements, and herbal products. It is important to discuss all medications and supplements you take with your doctor, as they may affect how your HIV medications work. In some cases, they may cause adverse reactions.

Antiretroviral drugs may have side effects. However, the benefits of taking HIV medications generally outweigh the side effects because antiretroviral therapy helps people live long, healthy lives with less risk of complications and spreading the virus to others.

Potential side effects vary depending on the type of medicine a person is using. Possible short-term side effects of antiretroviral therapy may include:

• diarrhea;
• insomnia;
• dizziness;
• fatigue;
• headache;
• muscle pain;
• nausea;
• vomiting

Long-term side effects may include:

• depression;
• diabetes;
• heart diseases;
• insomnia;
• kidney damage;
• liver damage;
• nerve damage;
• bone weakness, osteoporosis;
• elevated blood cholesterol levels.

Side effects that indicate more serious complications and may require emergency treatment include:

• extreme fatigue;
• nausea;
• fever;
• constant vomiting;
• rash.

You can read more about the side effects of antiretroviral therapy and how to prevent them in our article .

When to start antiretroviral therapy?

WHO recommends that all people with HIV begin antiretroviral therapy as soon as possible. Timely initiation of treatment gives a greater chance of reducing the viral load and the risk of complications.

For some groups of people with HIV, it is especially important to seek treatment immediately. These groups include:

• people with early stage HIV;
• pregnant or breastfeeding women;
• people with AIDS (late stage of HIV);
• people with cancer and other dangerous diseases;
• people who have sex with people who do not have HIV.

Research shows that prompt treatment reduces the risk of transmission, disease progression, and complications. It also significantly increases life expectancy for many people.  

If a person with HIV does not receive treatment, the virus usually develops into AIDS within 10 years. AIDS causes irreversible damage to the immune system and a higher risk of infections and cancer.