Final answer:
The earliest drug used to treat AIDS was azidothymidine (AZT), also known as zidovudine or the brand name Retrovir. It became the first drug approved for the treatment of AIDS in 1987. Several other drugs have been developed since then to treat AIDS.
Step-by-step explanation:
The earliest drug used to treat AIDS was azidothymidine (AZT), also known as zidovudine or the brand name Retrovir. AZT became the first drug approved for the treatment of AIDS in 1987. It works by binding to reverse transcriptase, an enzyme involved in the replication of HIV, and blocking further replication. Since then, several other drugs have been developed to treat AIDS, including protease inhibitors and nucleoside analogs.