Efavirenz is an antiretroviral medication used to treat HIV infection. It belongs to a class of drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs), which work by blocking the reverse transcriptase enzyme, preventing the virus from replicating in the body. Typically taken once daily, Efavirenz is often combined with other antiretroviral medications to enhance its effectiveness. Common side effects may include dizziness, insomnia, and vivid dreams. Regular monitoring by a healthcare provider is essential to manage any potential adverse effects and ensure the treatment's success.