Drugs for HIV infection and AIDS
A range of drugs that are used to treat HIV infection and its complications.
Advances in drug treatments for people with HIV infection and AIDS have offered new hope by slowing or halting the progression of the disease and improving quality of life. The human immunodeficiency virus (HIV) infects and gradually destroys white blood cells of the body's immune system, known as CD4 lymphocytes, which normally help to fight infections. People with HIV infection may remain symptom-free for many years, or they may experience frequent or prolonged mild infections. If a specific infection or tumour occurs, a person is said to have developed AIDS (acquired immunodeficiency syndrome). These conditions, called AIDS-defining illnesses, include a number of severe infections, such as pneumocystis infection, toxoplasmosis, and certain cancers, such as Kaposi's sarcoma and non-Hodgkin's lymphoma.
|Reverse transcriptase inhibitors: Abacavir, Didanosine (ddl), Efavirenz (EFV), Lamivudine (3TC), Nevirapine (NVP), Stavudine (d4T), Tenofovir, Zalcitabine (ddC), Zidovudine (AZT)||Protease inhibitors: Amprenavir, Indinavir, Lopinavir, Nelfinavir, Ritonavir, Saquinavir|
Why are they used?
The drugs currently in use to treat HIV infection have made it possible to suppress the level of the virus in the blood, with the aim of reducing it so that the virus becomes undetectable. If this aim is achieved, the immune system can recover sufficiently to overcome or prevent infections. Experts believe that, in some people, the drugs may be able to prevent the progression of HIV infection to AIDS. Evidence to support this is very encouraging, and many people who use the newer drugs have shown a dramatic improvement in their condition. Treatment of HIV infection involves two distinct groups of drugs: antiretroviral drugs, which act against the virus itself, and anti-infective drugs such as antibiotics, which are used to treat the diseases that develop as a result of reduced immunity. Treatment with antiretroviral drugs is believed to be beneficial for anybody with HIV infection or AIDS, but expert opinion is still divided about the best time to begin this treatment. It is generally believed that the earlier treatment begins, the greater the possibility of altering the course of the disease. However, the drugs have severe side effects that are difficult to tolerate over years of treatment. Drug treatment is recommended at a later stage in the disease for people with falling numbers of CD4 lymphocytes or rising virus levels and people with an AIDS-defining illness. People who have been in contact with blood or other body fluids from a person with HIV are given immediate treatment with antiretroviral drugs for 1 month. Antiretrovirals are also recommended for HIV-positive mothers during pregnancy to reduce the risk of the baby being born with the virus.
How do they work?
There are two main groups of antiretroviral drugs used in the treatment of HIV infection and AIDS: reverse transcriptase inhibitors and protease inhibitors. The drugs work by blocking the processes necessary for viral replication without significantly damaging the body cells that the virus has invaded. Reverse transcriptase inhibitors, such as zidovudine (AZT), inhibit viral enzymes involved in replication. Protease inhibitors, such as ritonavir, prevent the production of viral proteins necessary for replication.
How are they used?
Treatment of HIV infection and AIDS is subject to rapid change as knowledge about the virus increases. Currently, antiretroviral drugs are generally used in combination to destroy the virus more effectively and help to prevent the development of drug-resistant strains of HIV. The drugs are taken orally, and often many tablets must be taken daily. It is important to take the drugs on time each day to help to prevent the emergence of drug resistance in HIV.
What are the side effects?
If you have HIV infection, your doctor will discuss your treatment options with you at length because the drugs have side effects that should be weighed against the benefits of treatment. Antiretroviral drugs can cause nausea, vomiting, and diarrhoea, which may be very severe. Other serious side effects include inflammation of the pancreas (see Acute pancreatitis) and damage to the nerves, eyes, liver, or kidneys. There may also be redistribution of body fat, and anaemia may develop. You need regular checkups and blood tests to look for warning signs of side effects. Pregnant women need expert advice on having treatment with antiretrovirals; these drugs can prevent transmission of HIV to the fetus but are potentially harmful to its development.
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