Azidothymidine (3'-azido 2'3'-dideoxythymidine, AZT, zidovudine, retrovir, Glaxo-Smithklein) - synthetic antiretroviral drugs, analogues of natural nucleoside thymidine - was proposed for the treatment of patients with HIV infection in 1985 and for a long time was one of the most effective antiviral agents.