Nvp
Name: NVP
Pharmacology
Mechanism of Action
Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI); activity against HIV-1 by binding to reverse transcriptase, and thereby blocking RNA- and DNA-dependent DNA polymerase actions including HIV-1 replication
Does not require intracellular phosphorylation for activity
Absorption
Bioavailability: >90%
Peak Plasma: 2-4 hr
Distribution
Distributed widely; crosses placenta; enters breast milk; CSF penetration approximates 50% of plasma
Protein Bound: 50-60%
Vd: 1.2-1.4 L/kg
Metabolism
Extensively hepatic via CYP3A4 (hydroxylation to inactive compounds)
May undergo enterohepatic recycling
Elimination
Half-life: Decreases over 2-4 wk with chronic dosing due to autoinduction (ie, half-life initially 45 hr and decreases to 23 hr)
Excretion: Urine (~81% as metabolites, <3% as unchanged drug); feces (10%)