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. Often combined with ritonavir, it helps enhance the effectiveness of the treatment while reducing the dosage needed. This medication is typically administered as part of a combination therapy, which means it is used alongside other antiretroviral drugs. Lopinavir is available in tablet form and as a liquid, making it accessible for different patient needs. Regular monitoring by healthcare professionals is essential to manage any potential side effects.