Ticlopidine hydrochloride is an antithrombotic proagent that acts as an allosteric, noncompetitive inhibitor of CD39 with an IC50 of 81.7 μM. It blocks several NTPDase isoenzymes, with IC50s of 170 μM for NTPDase2 and 149 μM for NTPDase3. This compound also inhibits CYP2C19 human liver cytochrome, as well as CYP2C9 and CYP3A4 with IC50s of 26.0 and 32.3 μM, respectively.