Azamulin is a selective, irreversible inhibitor of cytochrome P450 (CYP) 3A isoforms (IC50 values range from 26 to 240 nM for CYP3A4 and CYP3A4 5 from different sources). [1] It is at least 50-fold less potent against CYP2J2 and 100-fold less effective against all other CYP isoforms. [1] Azamulin potently blocks the hydroxylation of testosterone and midazolam by CYP3A4.[2]