In a study to assess inhibition of a series of P450 isoenzymes (CYP 1A2, 2C9, 2C19, 2D6, 2E1 and 3A4) incubated with 100 µM azacitidine, IC50 values could not be determined, therefore, enzyme inhibition by azacitidine at clinically achievable plasma concentrations is unlikely.