Though it is not possible to comletely eliminate HIV from the body, the goal of treatment is to keep the virus from reproducing. This is important because many studies have shown that people with high levels of virus in the blood (the viral load) will progress more rapidly to AIDS. The goal is achieve a viral load test that shows undetectable levels of HIV (the virus never goes away, just goes to very low levels). When the virus is not reproducing quickly, it is less likely to kill CD4 cells. As the CD4 cell count increases, the immune system regains strength.
When to start treatment
The International AIDS Society–USA is an organization that specializes in keeping physicians informed about the latest research in HIV/AIDS. It recommends that patients start taking antiviral medications (anti-retrovirals) before the CD4 count falls below 350 cells per cubic milliliter of blood. The exact timing of treatment depends on many factors, and doctors and patients should discuss the risks and benefits before starting therapy.
If the decision is made to start treatment, your doctor will choose a combination of anti-retrovirals to fight your HIV infection. Several medications must be used together—often called a drug cocktail or highly active anti-retroviral therapy (HAART). These medications attack HIV at multiple points in its growth cycle and are more effective in suppressing the virus. Combining drugs also limits the risk that HIV will become resistant to these medications. When HIV becomes resistant to antivirals, these drugs become much less effective in controlling the virus.
Anti-retroviral drugs
There are more than 20 anti-retroviral medications available in the United States today. Many of these come in combination form, making the total number of different "pills" available closer to 30. These drugs have two or three names and may be referred to by the generic name, trade name, or a three letter abbreviation (for example, AZT is also known by its generic name, zidovudine, and by its trade name, Retrovir). Currently available anti-retroviral drugs include:
- Nucleoside reverse transcriptase inhibitors (NRTIs) block HIV reproduction at the virus' "reverse transcriptase." Examples include zidovudine (Retrovir, AZT), didanosine (Videx, ddI), stavudine (Zerit, d4T), abacavir (Ziagen, ABC), emtricitabine (Emtriva, FTC) and lamivudine (Epivir, 3TC) Tenofovir (Viread) is a commonly prescribed drug in a related family (nucleotide reverse transcriptase inhibitors). There are many NRTI combination pills including lamivudine and zidovudine (called Combivir) and emtricitabine and tenofovir (called Truvada).
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs) act on the same HIV reverse transcriptase that the NRTIs block, but at a different location. Drugs in this class include nevirapine (Viramune) and efavirenz (Sustiva)
- Protease inhibitors (PIs) block the assembly of new HIV virus particles (they inhibit the virus' "protease"). Atazanavir (Reyataz), darunavir (Prezista), fosamprenavir (Lexiva), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir), saquinavir (Invirase), and Tipranavir (Aptivus) are all Pis. PIs are often "boosted" with ritonavir to increase potency. Lopinavir and ritonavir are combined into one pill (Kaletra) for this purpose.
- Cell entry blockers block the virus at the cell surface. A fusion inhibitor called enfuvirtide (Fuzeon) and a CCR5 co-receptor antagonist, called maraviroc (Selzentry), are currently the only medications available that block HIV from getting inside the cell in the first place. Enfuvirtide is only available in injectable form.
- Integrase inhibitor. Raltegravir (Isentress) is the only medication available today that blocks the "integration" of the virus’ genetic material with the cell’s genetic material. This blocks HIV from reproducing inside the cell.
Which drugs are right for you?
Numerous combinations can be made depending on patient and doctor preference. Because many of these drugs have side effects, such as nausea and diarrhea, the exact medications prescribed for a particular person may depend on side effects (which will vary from person to person).
The most commonly recommend initial therapy is a combination of the NNRTI efavirenz (Sustiva) and two NRTIs. A potential choice for people who are likely to miss doses of medication is a combination pill called Atripla. It contains efavirenz, emtricitabine, and tenofovir. Atripla is taken as one pill, once per day.
It is very important to tell your doctor about ALL other medications you take (including herbals and non-prescription medication) because there can be serious interactions with commonly used medications. Also, no one should take an anti-retroviral medication that was not specifically prescribed for them by a health care provider.
In addition to anti-retrovirals, people with low CD4 counts should take drugs to prevent the development of opportunistic infections. For example, people with CD4 cell counts below 200 cells per milliliter of blood should take trimethoprim-sulfamethoxazole (known as Bactrim or Septra) to protect themselves against
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