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(zīdō`vyo͞odēn'), drug used to treat patients infected with the human immunodeficiency virus (HIVHIV,
human immunodeficiency virus, either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States.
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), which causes AIDSAIDS
or acquired immunodeficiency syndrome,
fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neurological disorders. It was first recognized as a disease in 1981.
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; also called azidothymidine. Originally developed in 1964 as an anticancer drug, AZT was never approved for that purpose. In 1984, Burroughs-Wellcome Company, which owned the rights to the drug, reexamined it as part of a search for any antiviral drugantiviral drug,
any of several drugs used to treat viral infections. The drugs act by interfering with a virus's ability to enter a host cell and replicate itself with the host cell's DNA.
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 that might be effective against the AIDS virus. It was approved by the FDA in 20 months, rather than the usual 8 to 10 years, in part for humanitarian reasons; thousands of people were dying of AIDS, no other treatment was forthcoming, and AIDS activists were lobbying heavily for approval.

AZT affects HIV's ability to reproduce by inhibiting the transcription of RNA to DNA. Although AZT can be helpful in the short term by promoting weight gain, decreasing the number of opportunistic infections, and improving T4 (CD4) lymphocyte counts (see immunityimmunity,
ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
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), some researcher believe studies of its effectiveness to be flawed and regard the drug as too toxic for long-term use. There is also a question of whether it is helpful in HIV-positive, asymptomatic people. AZT does not cure or prevent AIDS, nor does it keep one from transmitting the virus to others, although some studies show that it does lessen the possibility that an HIV-infected mother will transmit the virus to her fetus.

Adverse effects include bone marrow depression, headache, nausea, muscle pain, and a reduction in the number of certain white blood cells. The risk of side effects increases when certain other drugs, including acetaminophenacetaminophen
, an analgesic and fever-reducing medicine. It is an active ingredient in many over-the-counter medicines, including Tylenol and Midol. Introduced in the early 1900s, acetaminophen is a coal tar derivative that acts by interfering with the synthesis of
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, are taken at the same time.

References in periodicals archive ?
Data were analyzed from the perspective of an intention to treat in which participants from AZ MDA-treated villages who refused treatment were classified with those who accepted AZT as members of treatment villages.
They compared immunological restoration 1 year and 5 years after the initiation of treatment between individuals treated with AZT and those taking an alternative NRTI.
When TDF stocks are adequate, patients can transition immediately back to TDF from d4T or AZT if they are virologically controlled and have normal creatinine levels.
AZT works by inhibiting an enzyme, reverse transcriptase, which HIV needs to produce DNA from RNA, and thus replicate itself.
Now available at around 30% of their official post complement in most rural state hospitals, doctors are also concerned that the new official PMTCT guidelines speak of AZT and nevirapine (schedule IV drugs) having to be 'prescribed by a medical officer'.
The issue of a worldwide shortage of Retrovir brand AZT or ZDV (zidovudine) manufactured and marketed by GSK first came to AHF's attention last month during a meeting in Lusaka, Zambia, concerning the scale up of an anti-retroviral treatment program funded by PEPFAR.
He] declined a second course of AZT, but the ill effects of the first course failed to resolve.
But a study headed by Louise Kuhn of Columbia University, reported in the July issue of the Journal of Infectious Diseases, found that AZT exposure was associated with increased risk of death among infants.
The findings allay the fear that AZT use by pregnant women may lead to cardiac abnormalities in their children, the researchers said.
Approved December 31, 1990 for the treatment of anemia related to AZT therapy in HIV infection.
Researchers reported that significantly more antiretroviral-naive patients taking Sustiva in combination with AZT and 3TC exhibited suppressed levels of HIV to below quantifiable levels (less than 400 copies/mL) than people taking indinavir in combination with AZT and 3TC.
But because tests in animals show that AZT exposure might cause cancer, researchers have worried that AZT might harm the children.