When AIDS first surfaced in the United States, there were no drugs to combat the underlying immune deficiency, and few treatments existed for the opportunistic diseases that resulted. Researchers, however, have developed drugs to fight both HIV infection and its associated infections and cancers.
HIV infection
The Food and Drug Administration (FDA) has approved a number of drugs for treating HIV infection.
RT Inhibitors
The first group of drugs, called reverse transcriptase (RT) inhibitors, interrupts an early stage of the virus, making copies of itself. Nucleoside/nucleotide RT inhibitors are faulty DNA building blocks. When these faulty pieces are incorporated into the HIV DNA (during the process when the HIV RNA is converted to HIV DNA), the DNA chain cannot be completed, thereby blocking HIV from replicating in a cell. Non-nucleoside RT inhibitors bind to reverse transcriptase, interfering with its ability to convert the HIV RNA into HIV DNA. This class of drugs may slow the spread of HIV in the body and delay the start of opportunistic infections.
Protease Inhibitors
FDA has approved a second class of drugs for treating HIV infection. These drugs, called protease inhibitors, interrupt the virus from making copies of itself at a later step in its life cycle.
Fusion Inhibitors
FDA also has introduced a third new class of drugs, known at fusion inhibitors, to treat HIV infection. Fuzeon (enfuvirtide or T-20), the first approved fusion inhibitor, works by interfering with the ability of HIV-1 to enter into cells by blocking the merging of the virus with the cell membranes. This inhibition blocks HIV’s ability to enter and infect the human immune cells. Fuzeon is designed for use in combination with other anti-HIV treatments. It reduces the level of HIV infection in the blood and may be effective against HIV that has become resistant to current antiviral treatment schedules.
Because HIV can become resistant to any of these drugs, healthcare providers must use a combination treatment to effectively suppress the virus. When multiple drugs (three or more) are used in combination, it is referred to as highly active antiretroviral therapy, or HAART, and can be used by people who are newly infected with HIV as well as people with AIDS. Recently, FDA approved the first one-a-day, three-drug combination pill called Atripla.
Researchers have credited HAART as being a major factor in significantly reducing the number of deaths from AIDS in this country. While HAART is not a cure for AIDS, it has greatly improved the health of many people with AIDS, and it reduces the amount of virus circulating in the blood to nearly undetectable levels. Researchers, however, have shown that HIV remains present in hiding places, such as the lymph nodes, brain, testes, and retina of the eye, even in people who have been treated.
Side effects
Despite the beneficial effects of HAART, there are side effects associated with the use of antiviral drugs that can be severe. Some of the nucleoside RT inhibitors may cause a decrease of red or white blood cells, especially when taken in the later stages of the disease. Some may also cause inflammation of the pancreas and painful nerve damage. There have been reports of complications and other severe reactions, including death, to some of the antiretroviral nucleoside analogs when used alone or in combination. Therefore, health experts recommend that anyone on antiretroviral therapy be routinely seen and followed by their healthcare provider.
The most common side effects associated with protease inhibitors include nausea, diarrhea, and other gastrointestinal symptoms. In addition, protease inhibitors can interact with other drugs, resulting in serious side effects. Fuzeon may also cause severe allergic reactions such as pneumonia, difficult breathing, chills and fever, skin rash, blood in urine, vomiting, and low blood pressure. Local skin reactions are also possible since it is given as an injection underneath the skin. People taking HIV drugs should contact their healthcare providers immediately if they have any of these symptoms.
Opportunistic infections
A number of available drugs help treat opportunistic infections. These drugs include
Foscarnet and ganciclovir to treat CMV (cytomegalovirus) eye infections
Fluconazole to treat yeast and other fungal infections
TMP/SMX (trimethoprim/sulfamethoxazole) or pentamidine to treat PCP (Pneumocystis carinii pneumonia)
Healthcare providers use radiation, chemotherapy, or injections of alpha interferon—a genetically engineered protein that occurs naturally in the human body—to treat Kaposi’s sarcoma or other cancers associated with HIV infection.

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