Clopidogrel Bisulfate: A Review of its Use in the Management of Acute Coronary Syndrome

Antiplatelet therapy is the cornerstone in the modern therapy of patients with acute coronary syndromes (ACS), because of the unique role of platelets in coronary thrombosis. Clopidogrel in combination with aspirin is the current “gold standard” for reducing cardiovascular events in such patients, providing a synergistic platelet inhibition through different platelet activation pathways. Clopidogrel is a thienopyridine which inhibits ADP-induced platelet aggregation, with no direct effects on the metabolism of arachidonic acid. Due to a better safety profile with a similar antiplatelet effectiveness, it is preferred to ticlopidine. In patients with ACS without ST segment elevation (NSTEMI), clopidogrel plus aspirin is able to reduce the relative risk of adverse cardiovascular events by 20%, compared with aspirin alone. Clopidogrel plays a key role also in patients undergoing coronary stenting, in order to prevent stent thrombosis. Pretreatment and long-term treatment with clopidogrel reduces by about one-third the risk of cardiovascular death or myocardial infarction in NSTEMI ACS patients undergoing percutaneous coronary angioplasty (PCI). However, a long-term dual antiplatelet therapy is associated with a higher rate of bleeding events. Clinical practice guidelines currently recommend long-term dual antiplatelet therapy with aspirin and clopidogrel in patients with ACS and a pre-treatment with clopidogrel in every patient scheduled for PCI. The concept of clopidogrel resistance and the need for a pretreatment in patients undergoing coronary stent implantation led to the concept that an improved antiplatelet regimen with novel drugs is desirable.