Emtricitabine is an antiviral medication primarily used to treat HIV infection. It belongs to a class of drugs known as nucleoside reverse transcriptase inhibitors (NRTIs), which work by blocking the reverse transcriptase enzyme, preventing the virus from replicating in the body. This medication is often prescribed as part of a combination therapy to enhance its effectiveness and reduce the risk of developing drug resistance. Emtricitabine is usually taken orally in the form of a tablet or liquid, and it is important for patients to adhere to their prescribed regimen for optimal results.