HIV, also known as the human immunodeficiency virus, infects and destroys special immune cells known as T cells. Initially after infection, the immune system is able to combat the virus. Because the virus attacks the immune system, however, over time the body is not able to fight it off and the immune system becomes depleted. HIV medications are able to slow the progression of the virus.
NRTIs
Nucleoside reverse transcriptase inhibitors (NRTIs) are one form of medication for an HIV infection. As the Mayo Clinic explains, these drugs inhibit the protein the virus uses to copy its genetic material into the cell (reverse transcriptase). These medications, which include abacavir, zidovudine and stavudine, are able to mimic nucleosides (pieces of genetic material) but block reverse transcriptase's action instead of being incorporated into the genome of the host cells.
NNRTIs
Non-nucleoside reverse transcriptase inhibitors (NNRTIs) work similarly to NRTI medications except that they do not resemble nucleosides. Instead, they bind to the reverse transcriptase protein and disable it, which prevents the virus from replicating. According to AIDS Info, examples of these medications include etravirine and efavirenz.
Protease Inhibitors
In order for the HIV virus to mature within the cells, it needs to be processed by special proteins called proteases. Proteases activate the viral proteins once the virus has infected human immune cells. Protease inhibitors, which include ritonavir, amprenavir and saquinavir, keep these proteins from activating the virus. These drugs keep the human immunodeficiency virus from being sufficiently organized to replicate within human cells.
Fusion Inhibitors
Fusion inhibitors are designed to keep HIV from infiltrating human cells. For HIV to enter a immune cell, it has to fuse its membrane, a protective outer layer of proteins and lipids, with the membrane of the immune cells. Fusion inhibitors, which include the drug enfuvirtide, prevent that from happening.
Chemokine Co-receptor Inhibitors
HIV is unusual in that it has to bind to special proteins called chemokine co-receptors, in order to enter a host cell. Chemokine co-receptor inhibitors work to block these proteins, thus preventing the virus from entering host cells. According to the Mayo Clinic, maraviroc is the only approved drug in this class of anti-HIV medications.
