Evaluation of clopidogrel resistance

Clopidogrel resistance

Clopidogrel resistance has been used as one of the terms employed in the literature to describe different degrees of ex vivo low platelet inhibition after clopidogrel administration. In addition to the diverse nomenclature, the characterisation of clopidogrel resistance has also been problematic because different authors have given different definitions. The mechanisms responsible for this decreased platelet response are not yet clearly defined, some hypotheses have been put forward but not yet demonstrated. Although there have been no large prospective studies demonstrating that the degree of platelet inhibition is directly related to clinical outcomes, several recent studies and reports have shown an association between less platelet inhibition and more adverse events after percutaneous coronary interventions with clopidogrel therapy suggesting that clopidogrel resistance may be a marker for increased risk of recurrent cardiovascular events. Larger scale investigations are needed to support these findings.

Optimal antiplatelet treatment for percutaneous coronary intervention: Clopidogrel vs. ticlopidine

Antiplatelet treatment for patients undergoing percutaneous coronary interventions is a rapidly changing area. Thienopyridines derivatives (ticlopidine and clopidogrel) have shown to decrease major cardiovascular events. Ticlopidine can cause rare but serious side effects, especially during the first 3 months of treatment. Clopidogrel appears to be a safer alternative to ticlopidine. However, resistance to clopidogrel therapy may increases the risk of recurrent cardiovascular events. Whether increased doses of clopidogrel might overcome this resistance in nonresponsive patients warrants further investigation.