No cure exists for HIV (Human Immunodeficiency Virus), the virus that causes AIDS. Treatment options focus on slowing the replication of the virus. As HIV enters the body, it attacks the CD4 cells, specific type of white blood cell necessary for fighting infections. Once inside the CD4 cells, the virus incorporates its genetic material into the DNA (deoxyribose nucleic acid), or genetic code, of the cell. As the cell works to make new proteins, it also produces new copies of the virus. The most effective treatments, according to HIV Info Source, use a combination of medications to suppress replication of the virus and prevent the virus from developing a resistance to the medications.
Nucleoside Reverse Transcriptase Inhibitors
To understand how Nucleoside Reverse Transcriptase Inhibitors (NRTI) work to treat HIV infection, you must first understand the basics of how HIV works within the cells. The genetic code of the HIV virus is in the form of RNA, which is ribonucleic acid. RNA is similar to DNA and can be turned into DNA with the help of a reverse transcriptase enzyme, a specific type of protein.
NRTIs, also referred to as "nukes," contain defective nucleosides, which along with phosphate groups are what make nucleotides, the building blocks of both DNA and RNA. As the reverse transcriptase enzyme works to convert the viral RNA into DNA it uses the defective nucleosides resulting in incorrect DNA that cannot incorporate into the cell's DNA. This prevents the cell from producing more virus keeping viral count low.
Common NRTIs include zidovudine (commonly known as AZT), didanosine, zalcitabine, stavudine, lamivudine and abacavir.
Nucleotide Reverse Transcriptase Inhibitors
Nucleotide Reverse Transcriptase Inhibitors (NtRTIs) work very similar to the NRTIs by interfering with the nucleotides of the reverse transcriptase enzyme. The difference between NtRTIs and NRTIs is that the NtRTIs contain defective nucleotides which are are already chemically active and do not need to undergo phosphorylation, the addition of a phosphate group, in order to be active.
Adefovir is a NtRTI that is usually used as a treatment only after patients have failed to respond to NRTI treatment. Adefovir can cause side effects including nausea and vomiting.
Non-Nucleoside Reverse Transcriptase Inhibitors
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) are anti-viral medications that attach themselves to the reverse transcriptase enzyme and prevent the enzyme from converting the viral RNA into DNA. This prevents the virus's genetic code from incorporating into the cell, which in turn prevents the cell from making new virus.
Common NNRTI include nevirapine, which can cause a serious rash, delavirdine and efavirenz, which can interfere with the levels of other antiviral medications.
Protease Inhibitors
Once the viral genetic material has been incorporated into cells, the cells are "programmed" to make new copies of HIV and HIV proteins, according to information provided by AidsMeds.com. In order to make the new functional proteins; however, enzymes known as proteases must cut up the proteins. Protease inhibitors, such as saquinavir, ritonavir, indinavir and nelfinavir, inhibit the protease enzyme from functioning, which prevents new virus from being produced.
