Mechanism of Action

Binds to the site of HIV-1 protease activity and inhibits cleavage of viral Gag-Pol polyprotein precursors into individual functional proteins required for infectious HIV. This results in the formation of immature, noninfectious viral particles.

Pharmacodynamics/Kinetics

Absorption: Incomplete (percentage not established)

Distribution: V_d: 7.7-10 L

Protein binding: >99% (albumin, alpha₁-acid glycoprotein)

Metabolism: Hepatic, via CYP3A4 (minimal when coadministered with ritonavir)

Bioavailability: Not established

Half-life elimination: Children 2-<6 years of age: ~8 hours, 6-<12 years of age: ~7 hours, 12-18 years: ~5 hours; Adults: 6 hours

Time to peak, plasma: 3 hours

Excretion: Feces (82%); urine (4%); primarily as unchanged drug (when coadministered with ritonavir)