Clopidogrel and antiplatelet therapy

Abstract

Large clinical trials performed with ticlopidine in patients with atherosclerotic arterial diseases showed that ticlopidine was of benefit to patients who were at high risk of vascular events and demonstrated that it was likely to be more efficacious than other antiplatelet drugs tested to date. The search for other active antiplatelet drugs within the original chemical class of the thienopyridines led to the discovery of a new molecule: clopidogrel. Clopidogrel is a novel ADP-selective agent whose antiaggregating properties are several times higher than those of ticlopidine and are apparently due to the same mechanism of action (inhibition of ADP binding to its platelet receptor). This effect has been seen in various experimental animal species as well as in healthy volunteers and in atherosclerotic patients. Of particular interest is the ability of this drug to prevent arterial as well as venous thrombosis in animals and also to reduce myointimal thickening occurring after endothelial injury of the rabbit carotid artery. Clopidogrel seems to be better tolerated than ticlopidine and, on the basis of the activity/toxicity ratio observed, appears to be a promising compound for evaluation in atherosclerotic cardiovascular and cerebrovascular diseases. The outcome of clinical trials currently in progress could provide definite evidence of clopidogrel's efficacy.