This is the first of a set of treatment pages that give an overview of the issues surrounding HIV and AIDS treatment. It is followed by starting treatment and continuing treatment.

What is HIV antiretroviral treatment?

This is the main type of treatment for HIV or AIDS. It is not a cure, but it can stop people from becoming ill for many years. The treatment consists of drugs that have to be taken every day for the rest of someone's life. To understand more about treatment you need to have some basic knowledge of HIV and AIDS.

Antiretroviral treatment for HIV infection consists of drugs which work against HIV infection itself by slowing down the replication of HIV in the body. The drugs are often referred to as:

• antiretrovirals
• anti-HIV drugs
• HIV antiviral drugs

What is Combination Therapy, what is HAART?

For antiretroviral treatment to be effective for a long time, it has been found that you need to take more than one antiretroviral drug at a time. This is what is known as Combination Therapy. The term Highly Active Antiretroviral Therapy (HAART) is used to describe a combination of three or more anti-HIV drugs.

When HIV replicates (makes new copies of itself) it often makes mistakes. This means that within any infected person there are many different strains of virus. Occasionally, a new strain is produced that happens to be resistant to the effects of an antiretroviral drug. If the person is not taking any other type of drug then the resistant strain is able to replicate quickly and the benefits of treatment are lost.

Taking two or more antiretrovirals at the same time vastly reduces the rate at which resistance develops.

The groups of antiretroviral drugs

There are four groups of anti-HIV drugs. Each of these groups attacks HIV in a different way.

Nucleoside/Nucleotide Reverse Transcriptase Inhibitors

The first group of antiretroviral drugs are the Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs). These were the first type of drug available to treat HIV infection in 1987. NRTIs (also known as nucleoside analogues or nukes) interfere with the action of an HIV protein called reverse transcriptase, which the virus needs to make new copies of itself. NRTIs are sometimes called the "backbone" of combination therapy because most regimens contain at least two of these drugs.

Although these medications are used as a first line for HIV treatment the rate at which antiretrovirals decrease viral loads is affected by:

• CD4+ cell counts at the beginning of treatment.
• Viral load at the beginning of treatment.
• The dosage of the drugs.
• Whether the drugs are taken exactly as prescribed.
• Whether antiretroviral drugs have been taken before.
• Whether any opportunistic infections are present.

SIDE EFFECTS:

Antiretroviral drugs can cause changes in the distribution of body fats or a more serious side effect called lactic acidosis (too much acid in the blood). Lactic acidosis causes rapid breathing, excessive sweating, cool and clammy skin, sweet-smelling breath, abdominal pain, nausea or vomiting, and coma. In addition, each drug may be associated with its own unique side effects. Some nucleosides may be associated with lipoatrophy, loss of the layer of fat under the skin of the face, arms, and legs.

Abacavir

A serious, potentially life-threatening allergic reaction occurs in a small number of people who take abacavir. Symptoms of this allergic reaction may include:

• Fever.
• Muscle aches.
• Diarrhea.
• Rash.
• Nausea or vomiting.
• Abdominal pain.
• Severe fatigue.
• Cough.

Didanosine

Side effects of didanosine may include:

• Inflammation of the pancreas ( pancreatitis), which can lead to abdominal pain and vomiting. This side effect is more common in people who drink alcohol heavily.
• Numbness, tingling, and painful sensations in the hands and feet ( peripheral neuropathy).
• Nausea or vomiting.
• Diarrhea.

Lamivudine

Side effects of lamivudine are uncommon but may include:

• Kidney problems.
• Reduced numbers of red blood cells ( anemia).
• Reduced numbers of a certain type of white blood cell ( neutropenia).

People who are infected with hepatitis B may have a flare-up of the illness if they suddenly stop taking lamivudine.

Stavudine

Side effects of stavudine may include numbness, tingling, or pain in the hands and feet (peripheral neuropathy). Stavudine may also be associated with lipoatrophy, loss of the layer of fat under the skin of the face, arms, and legs.

Tenofovir

Side effects of tenofovir may include nausea or vomiting, diarrhea, or weakness.

Serious side effects of tenofovir can include kidney problems.

Zidovudine

Side effects of zidovudine may include:

• Nausea or vomiting.
• Vague feeling of weakness or discomfort (malaise).
• Headache.
• Reduced numbers of red blood cells (anemia).
• Severe fatigue.
• Insomnia.

Abacavir, zidovudine, and lamivudine combinations

Side effects of any combination of abacavir, zidovudine, and lamivudine include side effects of all three drugs, such as:

• Fever.
• Cough.
• Nausea or vomiting.
• Diarrhea.
• Abdominal pain.
• Severe fatigue.
• Rash.

Emtricitabine

Side effects of emtricitabine can include:

• Headache.
• Diarrhea.
• Nausea.
• Rash.
• Skin discoloration.

Serious side effects of emtricitabine can include severe liver problems.

People who are infected with hepatitis B may have a flare-up of the illness if they suddenly stop taking emtricitabine.

Emtricitabine and tenofovir combination

Side effects of a combination of emtricitabine and tenofovir may include:

• Nausea or vomiting.
• Diarrhea.
• Rash.
• Lack or loss of strength.
• Passing of gas.
• Weight loss.

Report all side effects to your health professional at your next visit. He or she can adjust your dose or give you other drugs to reduce side effects. Some mild side effects, such as nausea, improve as your body adjusts to the drug.

Non-Nucleoside Reverse Transcriptase Inhibitors

The second group of antiretroviral drugs are the Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs), which started to be approved in 1997. Like the nukes, NNRTIs (also known as non-nucleosides or non-nukes) stop HIV from replicating within cells by inhibiting the reverse transcriptase protein.

these medication can be used in combination with NRTIs to treat HIV.

Side effects:

Side effects of nevirapine may include:

• Headache.
• Liver problems, which can be severe and life-threatening. Regular blood tests may be needed to monitor for liver problems.
• Nausea.
• Rash, which can be severe.

Side effects of delavirdine mesylate may include:

• Dizziness.
• Fatigue.
• Headache.
• Nausea, vomiting, and diarrhea.
• Rash.

Side effects of efavirenz may include:

• Difficulty sleeping (insomnia).
• Dizziness.
• Drowsiness (sedation).
• Vivid dreams.

What To Think About

Like several other anti-HIV drugs, emtricitabine (Emtriva) is taken only once a day. If you have trouble taking multiple drugs throughout the day, you may want to ask your health professional whether Emtriva is right for you. Emtriva is always combined with at least 2 other anti-HIV drugs to treat HIV or AIDS.

Resistance to single-drug NNRTI treatment may develop quickly. For this reason, they should be used only in combination with other antiretroviral drugs to treat HIV infection or to prevent or delay the development of resistance.

Efavirenz can be taken once a day.

Efavirenz should not be taken at the same time as voriconazole (Vfend), a drug that is used to treat serious fungal infections. Talk to your doctor about all drugs you are taking before starting a new drug.

Factors to consider when choosing a drug combination include:

• The drugs' abilities to reduce your viral load.
• The likelihood that you will develop drug resistance. If you have already been treated with a certain antiretroviral drug, you may already know whether you are resistant to drugs in that class.
• Side effects and your willingness to tolerate them.
• The cost of treatment.

Protease Inhibitors

The third type of antiretrovirals is the protease inhibitor (PI) group. The first protease inhibitor was approved in 1995. Protease inhibitors, as the name says, inhibit protease, which is another protein involved in the HIV replication process.

SIDE EFFECTS:

PIs may cause potentially serious or life-threatening medication interactions. It is important to learn which medications should not be taken with PIs and other antiretroviral medications to prevent serious medication interactions or decrease medication effectiveness.

PIs may cause:

• An increase in blood sugar.
• Redistribution of body fat.
• An increase in cholesterol and triglycerides.

In addition, each medication may be associated with its own unique side effects.

Saquinavir (Fortovase, Invirase)

Saquinavir's side effects may include:

• Diarrhea.
• Nausea.
• Abdominal pain.
• Rash.

Ritonavir (Norvir)

Ritonavir has the most severe side effects, although these can be reduced if the first doses are small and increased gradually. Side effects may include:

• Diarrhea.
• Nausea or vomiting.
• Loss of appetite.
• Headache.
• Fatigue or weakness.
• Tingling around the mouth.
• Changes in the way foods taste.

Indinavir (Crixivan)

Indinavir's side effects may include:

• Kidney stones (nephrolithiasis), which have been reported in 5% of people who use this medication. The risk of kidney stones can be decreased by drinking at least 48 fl oz (1.4 L) of fluid each day.
• Mild stomach problems.

Nelfinavir (Viracept)

Nelfinavir's most common side effect is diarrhea, which may be severe. Diarrhea can usually be controlled with nonprescription medication such as loperamide (for example, Imodium AD or Kaopectate) or calcium supplements, such as Tums.

Lopinavir and ritonavir (Kaletra)

Side effects of lopinavir and ritonavir include:

• Diarrhea.
• Fatigue.
• Headache.
• Nausea.
• Increased cholesterol and triglyceride levels, which may require treatment.
• Pancreatitis.

Atazanavir (Reyataz)

Side effects of atazanavir include:

• Increased levels of bilirubin, a pigment found in the liver, which can make the skin, nails, and whites of the eyes appear yellow.
• Abnormal heartbeat
• Headaches.
• Pain or numbness in the arms and legs.
• Nausea, diarrhea, abdominal cramps.
• Rash.

Fosamprenavir (Lexiva)

Side effects of fosamprenavir include:

• Appetite loss.
• Headache.
• Diarrhea, nausea, and vomiting.
• Abnormal fat distribution on the body.

Report all side effects to your health professional at your next visit. He or she can adjust your dose or give you other medications to reduce side effects. Some mild side effects, such as nausea, improve as your body adjusts to the medication.

Fusion or Entry Inhibitors

The fourth group of antiretrovirals is comprised of entry inhibitors, including fusion inhibitors. One of these drugs - commonly called T-20 - has been licensed both in the US and in Europe since 2003, but only for use by people who have already tried other treatments. The T-20 fusion inhibitor differs from the other antiretrovirals in that it needs to be injected (otherwise it would be digested in the stomach). Entry inhibitors prevent HIV from entering human cells.

Entry inhibitors work by preventing HIV from entering healthy T-cells in the body. They work differently than many of the approved anti-HIV drugs – the protease inhibitors (PIs), the nucleoside reverse transcriptase inhibitors (NRTIs), and the non-nucleoside reverse transcriptase inhibitors (NNRTIs) – which are active against HIV after it has infected a T-cell.

Entry inhibitors work by attaching themselves to proteins on the surface of T-cells or proteins on the surface of HIV. In order for HIV to bind to T-cells, the proteins on HIV's outer coat must bind to the proteins on the surface of T-cells. Entry inhibitors prevent this from happening. Some entry inhibitors target the gp120 or gp41 proteins on HIV's surface. Some entry inhibitors target the CD4 protein or the CCR5 or CXCR4 receptors on a T-cell's surface. If entry inhibitors are successful in blocking these proteins, HIV is unable to bind to the surface of T-cells and gain entry into the cells.

SIDE EFFECTS:

There have been reported side effects of this class of medication. These side effects include

What does a combination usually consist of?

Highly Active Antiretroviral Therapy consists of a combination of three or more drugs. The most common combination given to those beginning treatment consists of two NRTIs combined with either an NNRTI or a "boosted" protease inhibitor. Ritonavir (in small doses) is the drug most commonly used to boost a protease inhibitor. An example of a common combination is the two NRTIs zidovudine and lamivudine combined with the NNRTI efavirenz.

What if HAART is unavailable?

Although coverage has improved greatly in recent years, most people living with HIV in the developing world still have no access to antiretroviral treatment. Instead, the best they can hope to receive is treatment for the diseases that occur as a result of a weakened immune system, which are known as opportunistic infections. Such treatment has only short-term benefit because it does not address the underlying immune deficiency itself.