Human Immunodeficiency Virus (HIV) (cont.)

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What is the treatment for an HIV infection?

Medicines have been developed to inhibit almost all stages of the viral lifecycle. These are called highly active antiretroviral therapy (ART) and include the following:

  • Nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs) inhibit the ability of the virus to turn RNA into DNA. These medicines work by blocking the effect of a viral enzyme called reverse transcriptase. The virus needs to make DNA in order to insert it into the human genome. The earliest example of an NRTI was zidovudine (Retrovir), also known as AZT. NRTIs resemble the building blocks of nucleic acids and fool the enzyme into using them, which terminates the DNA strand.
  • Non-nucleoside reverse transcriptase inhibitors (NNRTIs) also block the reverse transcriptase enzyme, although in a slightly different way from NRTIs.
  • Protease inhibitors (PIs) inhibit a viral enzyme (protease) that the virus uses to turn long strands of protein into usable pieces. Viruses made in the presence of PIs are inactive and ineffective. A PI called ritonavir (Norvir) is used to increase (boost) the potency of other PIs.
  • Entry inhibitors were developed to keep viruses from entering cells.
  • Integrase inhibitors impair the ability of the transcribed viral DNA to insert into the human genome.

With so many options, it may be surprising that none of these drugs or combinations of these drugs has been shown to cure HIV. The problem lies in the ability of the virus to mutate and become resistant to medications. In addition, copies of the viral DNA can lie quietly in the human genome secluded from the ability of the drugs to act. This creates a latent reservoir for resurgent infection.

Treatment for individual patients depends on the sensitivity of their virus to medications, which can be measured though viral genotyping. Viral genotyping, a kind of drug resistance testing, determines if any anti-HIV medications will not be effective against a person's strain of HIV. Viral genotyping is recommended for all patients in the U.S.

Treatment may need to be individualized to minimize side effects in patients with underlying medical conditions, such as diabetes or heart disease. Pregnant patients should be treated by clinicians who are experts in this area and will not be covered the current article. However, it is important to note that treatment of HIV during pregnancy can dramatically reduce the risk of transmission to the unborn child.

Opinions on when to start ART have evolved over time. In 2013, the National Institutes of Health recommended that ART be given to all patients infected with HIV, regardless of the stage of infection. The goal of this recommendation was to reduce the risk of disease progression and to reduce the risk of contagion. Early treatment can also lead to reduction in HIV-associated inflammation and associated complications, which include cardiovascular and kidney disease. It is important to note that patients on treatment are not cured and can still spread the infection, but treatment reduces the amount of virus in contaminated fluids and therefore reduces the risk of spread.

Medically Reviewed by a Doctor on 3/3/2014