Lopinavir is a protease inhibitor that is manufactured by Abbott Laboratories. Protease inhibitors block the activity of the HIV protease (or proteinase) enzyme to slow HIV replication and delay damage to the immune system. During development, lopinavir was known as ABT-378.

Lopinavir must be taken with a low dose of ritonavir (Norvir), to slow the body’s processing of lopinavir boosts blood levels of the drug. This enhances the antiviral effect of lopinavir. Since Abbott manufactures both lopinavir and ritonavir, lopinavir is only available in combination with ritonavir. This combination is marketed as Kaletra.

For more information on lopinavir and Kaletra, see Kaletra.