Zidovudine, also known as AZT, is an antiretroviral medication used to treat HIV infection. It belongs to a class of drugs called nucleoside reverse transcriptase inhibitors (NRTIs), which work by blocking the reverse transcriptase enzyme, preventing the virus from replicating in the body. Zidovudine was the first drug approved for treating HIV and is often used in combination with other antiretroviral medications to enhance its effectiveness. Zidovudine can help improve the immune system and reduce the risk of developing AIDS or other related infections. Common side effects may include nausea, fatigue, and headaches. Regular monitoring by a healthcare provider is essential to manage any potential side effects and to ensure the medication is working effectively.