clopidogrel UK /klə(ʊ)ˈpɪd.əɡ.ɹɛl/US /kloʊˈpɪd.əˌɡɹɛl/ noun1 •An oral antiplatelet agent used to inhibit blood clots in coronary artery disease, peripheral vascular disease, and cerebrovascular disease, having the chemical formula C₁₆H₁₆ClNO₂S