Infection with human immunodeficiency virus, or HIV, causes AIDS, a condition in which the immune system becomes weakened, leaving patients vulnerable to life-threatening opportunistic infections. HIV is a retrovirus composed of a genome made from RNA molecules, surrounded by a protein capsule. The most common and effective drugs for treating HIV are antiretroviral medications which interfere with HIV replication, according to the international AIDS charity Avert.
HAART
No single drug can cure HIV, and doctors have found that cocktails of usually three or four antiretroviral medications taken together work most effectively, in a treatment program referred to as highly active retroviral therapy, or HAART. Several classes of HAART have been designed to combat HIV, each acting through different a mechanism. Doctors have not determined a single combination of drugs for every patient, as individual needs, drug responsiveness and side effects vary from patient to patient, according to a July 2010 article published in "Future Virology."
Reverse Transcriptase
HIV makes a DNA copy of its RNA genome from which new copies of the virus are generated inside host cells, as part of the natural life cycle of the virus. This process requires a viral enzyme called reverse transcriptase, which is a common target for many HIV medications, according to the website Cells Alive.
NRTI
During the RNA to DNA genome copying process of HIV, nucleoside and nucleotide reverse transcriptase inhibitor medications, or NRTIs, are recognized by reverse transcriptase in the same way as normal RNA molecules. These medications disrupt viral duplication by incorporating themselves into newly synthesized viral DNA, thereby preventing full duplication of the virus. Common types of NRTIs include zidovudine and didanosine, sold under the trade names of Retrovir and Videx respectively, according to a January 2010 article published in "Antiviral Research."
NNRTI
A class of drugs referred to as non-nucleoside reverse transcriptase inhibitors, or NNRTIs interfere with HIV viral duplication by binding directly to and inhibiting reverse transcriptase, thereby preventing the virus from copying its RNA genome into DNA. Common NNRTIs include efavirenz, nevirapine and delavirdine, sold under the trade names of Sustiva, Viramune and Rescriptor respectively, according to a January 2010 article published in "Antiviral Research."
PIs
Assembly of HIV viral proteins inside the host requires viral enzymes known as proteases which cut the HIV proteins in specific places, facilitating correct assembly of a functional virus. Antiviral actions of protease inhibitors, or PIs, are exerted through inhibition of viral proteases, interfering with assembly of the HIV virus. Saquinavir and ritonavir are common PIs, sold under the trade names of Invirase and Norvir respectively, according to an October 2009 article published in the "Brazilian Journal of Infectious Diseases."
References
- "Future Virology"; How HIV treatment could result in effective prevention; K. Venkatesh; July 2010
- Cells Alive: Human Immunodeficiency Virus
- "Antiviral Research"; Nucleoside and Nucleotide HIV reverse Transcriptase Inhibitors: 25 years After Zidovudine; T. Cihlar; Janurary 2010
- "Brazilian Journal of Infectious Diseases"; The Place of Protease Inhibitors in Antiretroviral Treatment; S. Tenor; October 2009
- Avert: Introduction to HIV and AIDS drug treatment
