Lopinavir is an antiviral medication primarily used to treat HIV infection. It works by inhibiting the protease enzyme, which is essential for the virus to replicate and spread in the body. Lopinavir is often combined with another drug called Ritonavir to enhance its effectiveness and improve its absorption. This medication is typically administered in the form of a tablet or liquid and is part of a comprehensive treatment plan that may include other antiretroviral drugs. Regular monitoring by a healthcare provider is essential to manage potential side effects and ensure the treatment's effectiveness.