NRTI stands for Nucleoside Reverse Transcriptase Inhibitor, a class of antiretroviral drugs used primarily to treat HIV infections. These medications work by blocking the action of reverse transcriptase, an enzyme that the virus needs to replicate its genetic material. By inhibiting this enzyme, NRTIs help reduce the viral load in the body, allowing the immune system to recover and function more effectively. Common examples of NRTIs include Zidovudine, Lamivudine, and Abacavir. These drugs are often used in combination with other antiretroviral medications to enhance their effectiveness and prevent the development of drug resistance. NRTIs are a crucial component of HAART (Highly Active Antiretroviral Therapy) for managing HIV.