Aprepitant

Absorption	The mean absolute oral bioavailability of aprepitant is approximately 60 to 65%.
Volume of distribution	70 L
Protein binding	>95%
Metabolism	Aprepitant is metabolized primarily by CYP3A4 with minor metabolism by CYP1A2 and CYP2C19. Seven metabolites of aprepitant, which are only weakly active, have been identified in human plasma. Enzyme Metabolite Reaction Km Vmax Cytochrome P450 1A2 5-({[(1R)-1-(4-fluorophenyl)-2-hydroxyethyl]amino}methyl)-2,3-dihydro-1H-1,2,4-triazol-3-one O-dealkylation Cytochrome P450 1A2 (2R)-2-(4-fluorophenyl)-2-{[(5-oxo-2,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]amino}acetic acid O-dealkylation Cytochrome P450 3A4 (2S,3R)-2-[(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethoxy]-3-(4-fluorophenyl)morpholine N-dealkylation 8.9 0.13 Cytochrome P450 3A4 5-({[(1R)-1-(4-fluorophenyl)-2-hydroxyethyl]amino}methyl)-2,3-dihydro-1H-1,2,4-triazol-3-one O-dealkylation Cytochrome P450 3A4 (2R)-2-(4-fluorophenyl)-2-{[(5-oxo-2,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]amino}acetic acid O-dealkylation Cytochrome P450 2C19 5-({[(1R)-1-(4-fluorophenyl)-2-hydroxyethyl]amino}methyl)-2,3-dihydro-1H-1,2,4-triazol-3-one O-dealkylation Cytochrome P450 2C19 (2R)-2-(4-fluorophenyl)-2-{[(5-oxo-2,5-dihydro-1H-1,2,4-triazol-3-yl)methyl]amino}acetic acid O-dealkylation
Route of elimination	Aprepitant is eliminated primarily by metabolism; aprepitant is not renally excreted. Aprepitant is excreted in the milk of rats. It is not known whether this drug is excreted in human milk.
Half life	9-13 hours
Clearance	Apparent plasma cl=62-90 mL/min
Toxicity	Not Available
Affected organisms	Humans and other mammals