The human immunodeficiency virus, or HIV, destroys white blood cells of the immune system called CD4+ cells. This leaves the body unable to protect itself against other invading organisms. When the virus damages enough of the immune system to make the body vulnerable, the state is called AIDS, or acquired immunodeficiency syndrome. Infection is generally contracted from blood, semen or vaginal fluids. HIV, which was first identified in the 1980s, has no cure, according to MayoClinic.com. There are many current treatments for HIV, however, that can help manage symptoms.
Nucleoside Analogs
HIV uses DNA to make new viruses. Nucleoside analogs are incorporated into growing DNA strands where they prevent the synthesis of new DNA by inhibiting the viral enzyme reverse transcriptase.
Side effects may include bone marrow suppression, pancreatitis, nausea, vomiting and allergic reactions. Nucleoside analogs include the drugs zidovudine, didanosine, lamivudine, stavudine, emtricitabine and abacavir.
Non-Nucleoside Reverse Transcriptase Inhibitors
Non-nucleoside reverse transcriptase inhibitors work similarly to nucleoside analogs. This class of drugs also inhibits the HIV enzyme reverse transcriptase so that the virus cannot make DNA. They bind directly to the enzyme instead of being incorporating into the DNA strand.
Common or concerning side effects include rash, mood disorders, liver damage and nausea. Drugs in this class include efavirenz, nevirapine, delavirdine and etravirine.
Protease Inhibitors
Protease inhibitors repress an ezyme called HIV-1 protease. When the virus makes proteins from DNA, the proteins are linked together in a long strand and need to be separated by HIV-1 protease in order to work. Without this enzyme, the proteins are stuck together.
Prominent side effects include digestive problems such as nausea and diarrhea. Other side effects include elevated fat and sugar in the blood and redistribution of fat in the body. Drugs of this class include ritonavir, darunavir, atazanavir, saquinavir nelfinavir, indinavir, amprenavir, lopinavir/ritonavir and tipranavir.
Integrase Inhibitors
Integrase inhibitors restrict the viral enzyme called integrase, which is responsible for integrating viral DNA into human DNA. Side effects include nausea, diarrhea, fever and headache. Raltegravir is the only drug in this class.
Fusion Inhibitors
Newly synthesized HIV is released into the body where it encounters white blood cells, fuses with them and enters the cells. Fusion inhibitors prevent this from happening.
The drug is administered by injection; side effects are generally from allergic reactions at the site of injection. Enfuvirtide is the only drug in this class of HIV medications.
CCR5 Inhibitors
CCR5 inhibitors also prevent entry of HIV particles into the CD4+ cells. It binds to the human protein CCR5 found on the CD4+ cells that HIV infects, and helps to prevent HIV from binding to the cells for entry. Side effects include cardiovascular effects including chest pain, as well as liver toxicity. Maraviroc is the only drug in this class.
References
- MayoClinic.com: HIV/AIDs: Treatments and drugs
- "Basic and Clinical Pharmacology"; Bertram Katzung, Susan Masters and Anthony Trevor; 11th Ed 2009
- AIDS Meds: Entry Inhibitors
