Human immunodeficiency virus, or HIV, is a devastating diagnosis. Over time, this infection progresses to acquired immunodeficiency syndrome, or AIDS. AIDS destroys the immune system, and the body cannot protect itself from invading micro-organisms. There is no cure for HIV, but anti-retroviral treatments have greatly increased the length and quality of life for those who are HIV-positive. Anti-retroviral drugs can prolong the time it takes for HIV to progress to AIDS. When a patient develops full-blown AIDS, secondary illnesses occur, and these must be treated individually
Non-nucleotide Reverse Transcriptase Inhibitors
When HIV infection occurs, the virus enters the immune cells and makes copies of its own genetic material. For this to occur, it must have an enzyme called reverse transcriptase. Non-nucleotide reverse transcriptase inhibitors, or NNRTIs, block reverse transcriptase to prevent viral DNA replication. These drugs have been used for HIV treatment since 1997. Approved NNRTI drugs include delaviridine, nevirapine and etravirine.
Nucleotide/Nucleoside Reverse Transcriptase Inhibitors
Nucleotide/nucleoside reverse transcriptase inhibitors, or NRTIs, also block the ability of HIV to replicate genetic material. Whereas NNRTIs block reverse transcriptase directly, NRTIs indirectly block the enzyme. NRTIs block replication by mimicking one of the HIV proteins in the replication process. Incorporating this faulty protein into its genetic material prevents reverse transcriptase from making HIV DNA. NRTIs include lamivudine, abacavir and zidovudine. Patients are often prescribed more than one NRTI, and multiple drugs can be combined into one pill for patients' convenience.
Protease Inhibitors
Protease inhibitors have been used since 1995 for HIV treatment. They prevent the action of the enzyme protease. The job of protease is to cut long strands of HIV genetic material so that it can function properly. Protease inhibitors cause several side effects, including diarrhea, nausea, vomiting and lipid abnormalities. Examples include amprenavir, fosamprenavir and atazanavir.
Entry/Fusion Inhibitors
Entry/fusion inhibitors block entry of HIV into the body's immune system cells. This contrasts with other HIV treatments that are not effective until the virus enters human cells. Entry inhibitors treat HIV by blocking receptor sites on either the HIV virus or the body's cells. If the viral proteins cannot bind to the cell receptors, the HIV virus is unable to enter the cell. Entry inhibitors include enfuvirtide and maraviroc. According to AidsMeds, a website founded by an HIV patient, entry inhibitors often prove useful for those who do not respond to other anti-retroviral drugs.
