Nucleoside reverse transcriptase inhibitors (NRTIs) are a class of antiviral medications used primarily to treat HIV infections. They work by blocking the action of reverse transcriptase, an enzyme that converts viral RNA into DNA, preventing the virus from replicating in the body. NRTIs are often part of combination therapy, which includes other types of antiretroviral drugs to enhance effectiveness and reduce the risk of drug resistance. Common NRTIs include zidovudine, lamivudine, and tenofovir, which help manage HIV and improve the quality of life for those living with the virus.