Lopinavir is a dicarboxylic acid diamide that is amphetamine is substituted on nitrogen by a (2,6-dimethylphenoxy)acetyl group and on the carbon alpha- to nitrogen by a (1S,3S)-1-hydroxy-3-{[(2S)-3-methyl-2-(2-oxotetrahydropyrimidin-1-yl)butanoyl]amino}-4-phenylbutyl group. An antiretroviral of the protease inhibitor class, it is used against HIV infections as a fixed-dose combination with another protease inhibitor, ritonavir. It has a role as an anticoronaviral agent, a HIV protease inhibitor and an antiviral drug. It is a member of amphetamines and a dicarboxylic acid diamide.