AZT (zidovudine, Retrovir)

AZT (zidovudine, Retrovir) is an anti-HIV drug that reduces the amount of virus in the body. Anti-HIV drugs such as AZT slow down or prevent damage to the immune system, and reduce the risk of developing AIDS-related illnesses .

AZT belongs to a class of drugs known as nucleoside reverse transcriptase inhibitors (NRTIs). When HIV infects a cell, the enzyme reverse transcriptase copies the viral single-stranded RNA genome into double-stranded viral DNA. This viral DNA is then integrated into the CD4 chromosomal DNA and can go on to reproduce in the body. Four natural nucleosides complete the DNA synthesis: adenosine, cytidine, quanosine, and thymidine. An NRTI drug substitutes a defective version of one of the nucleosides, causing premature termination of the proviral DNA chain.

The abbreviation AZT stands for azidothymidine. The drug is often referred to by its generic name, zidovudine, which is abbreviated to ZDV. Its chemical name is 3’-azido-3’-deoxythymidine.

AZT is manufactured under the trade name Retrovir by GlaxoSmithKline. Retrovir was the first drug licensed to treat HIV infection, having been approved by the United States Food and Drug Administration (FDA) in 1987. GlaxoSmithKline’s patent on AZT expired in September 2005. Consequently, generic versions of the drug can now be sold in the United States and the European Union.

A generic version called Zidovir is manufactured by the Indian manufacturer Cipla. Other generic versions of AZT include Viro-Z (Ranbaxy), Aviro-Z (Ranbaxy) and Zido-H (Genixpharma).

AZT is available combined with 3TC (lamivudine) in one pill, known by the trade name Combivir from GlaxoSmithKline. Each Combivir pill contains 300mg AZT and 150mg 3TC. Generic versions of this co-formulation include called Duovir (Cipla), Virocomb (Ranbaxy) and a version made by Aurobindo Pharma.

A pill that combines 300mg AZT, 150mg 3TC and 300mg abacavir, known as Trizivir, is also available from GlaxoSmithKline. It was approved in the United States in November 2000 and in the European Union in March 2001.