| Indication | For the reduction of atherosclerotic events (myocardial infarction, stroke, and vascular death) in patients with atherosclerosis documented by recent stroke, recent myocardial infarction, or established peripheral arterial disease |
| Pharmacodynamics | Clopidogrel, an antiplatelet agent structurally and pharmacologically similar to ticlopidine, is used to reduce atherosclerotic events such as myocardial infarction, stroke, and vascular death in patients who have had a recent stroke, recent MI, or have established peripheral vascular disease. |
| Mechanism of action | The active metabolite of clopidogrel prevents binding of adenosine diphosphate (ADP) to its platelet receptor, impairing the ADP-mediated activation of the glycoprotein GPIIb/IIIa complex. It is proposed that the inhibition involves a defect in the mobilization from the storage sites of the platelet granules to the outer membrane. he drug specifically and irreversibly inhibits the P2Y12 subtype of ADP receptor, which is important in aggregation of platelets and cross-linking by the protein fibrin. No direct interference occurs with the GPIIb/IIIa receptor. As the glycoprotein GPIIb/IIIa complex is the major receptor for fibrinogen, its impaired activation prevents fibrinogen binding to platelets and inhibits platelet aggregation. By blocking the amplification of platelet activation by released ADP, platelet aggregation induced by agonists other than ADP is also inhibited by the active metabolite of clopidogrel. |
| Absorption | Absorption is at least 50% based on urinary excretion of clopidogrel-related metabolites. Bioavailability has not been found to be affected by food. |
| Volume of distribution | Not Available |
| Protein binding | 98% |
| Metabolism | Hepatic, extensive and rapid, by hydrolysis to the main circulating metabolite, a carboxylic acid derivative, which accounts for approximately 85% of the circulating drug-related compounds. A glucuronic acid derivative of the carboxylic acid derivative has also been found in plasma and urine. Neither the parent compound nor the carboxylic acid derivative has a platelet inhibiting effect. |
| Route of elimination | Following an oral dose of 14C-labeled clopidogrel in humans, approximately 50% of total radioactivity was excreted in urine and approximately 46% in feces over the 5 days post-dosing. |
| Half life | Carboxylic acid derivative: 8 hours (after single and multiple doses). Covalent binding to platelets has accounted for 2% of radiolabeled clopidogrel with a half-life of 11 days. |
| Clearance | Not Available |
| Toxicity | Symptoms of acute toxicity include vomiting (in baboons), prostration, difficult breathing, and gastrointestinal hemorrhage. |