BACKGROUND AND PURPOSE Clopidogrel resistance is blamed for thromboembolic complications in neurovascular stent placement. Platelet-function assays are weakly standardized. The aim of this study was to correlate the results of 3 different platelet-inhibition measurements (from light transmission aggregometry, the VerifyNow P2Y12 test, and the Multiplate analyzer) and their relation to periproce...

OBJECTIVES This study sought to determine whether known genetic, drug, dietary, compliance, and lifestyle factors affecting clopidogrel absorption and metabolism fully account for the variability in clopidogrel pharmacokinetics and pharmacodynamics. BACKGROUND Platelet inhibition by clopidogrel is highly variable. Patients with reduced inhibition have increased risk for major adverse cardiova...

The P2Y12 receptor antagonist clopidogrel blocks platelet aggregation, improves systemic endothelial nitric oxide bioavailability, and has anti-inflammatory effects. Since P2Y12 receptors have been identified in the vasculature, we hypothesized that clopidogrel ameliorates angiotensin II (Ang II) -induced vascular functional changes by blockade of P2Y12 receptors in the vasculature. Male Spragu...

BACKGROUND Simultaneous prescription of clopidogrel and low-dose aspirin is recommended for the treatment of acute coronary syndrome because of improvements in efficacy and patient compliance. In this study, the pharmacokinetics of a fixed-dose combination (FDC) of clopidogrel and aspirin was compared with coadministration of individual formulations to clarify the equivalence of the FDC. METH...

BACKGROUND Prasugrel is more effective than clopidogrel in reducing platelet aggregation in acute coronary syndromes. Data available on prasugrel reloading in clopidogrel treated patients with high residual platelet reactivity (HRPR) i.e. poor responders, is limited. OBJECTIVES To determine the effects of prasugrel loading on platelet function in patients on clopidogrel and high platelet reac...

BACKGROUND Aspirin and clopidogrel therapy is associated with a variable bleeding risk in patients undergoing coronary artery bypass graft surgery (CABG). We evaluated the role of platelet function testing in clopidogrel-treated patients undergoing CABG. METHODS AND RESULTS One hundred eighty patients on background aspirin with/without clopidogrel therapy undergoing elective first time isolat...

1. Steinhubl SR, Berger PB, Mann 3rd JT et al. Early and sustained dual oral antiplatelet therapy following percutaneous coronary intervention: a randomized controlled trial. JAMA 2002;288:2411–20. [Erratum JAMA 2003; 289: 987]. 2. Eriksson P. Long-term clopidogrel therapy after percutaneous coronary intervention in PCI–CURE and CREDO: the ‘‘Emperor’s New Clothes’’ revisited. Eur Heart J 2004;2...

OBJECTIVE In addition to P2Y12 receptor antagonism, ticagrelor inhibits adenosine cell uptake. Prior data show that 7-day pretreatment with ticagrelor limits infarct size. We explored the acute effects of ticagrelor and clopidogrel on infarct size and potential long-term effects on heart function. APPROACH AND RESULTS Rats underwent 30-minute ischemia per 24-hour reperfusion. (1) Ticagrelor (...

BACKGROUND Some studies have suggested reduced activity of clopidogrel on platelet activation and adherence in patients using statins. OBJECTIVE To assess whether platelet activation and aggregation decrease with clopidogrel, and whether there is a reduction of the action of clopidogrel when associated with atorvastatin or simvastatin. METHODS This prospective study included 68 patients wit...

BACKGROUND The metabolic activation of clopidogrel is a two-step process. It has been suggested that paraoxonase-1 (PON1) is a rate-limiting enzyme in the conversion of 2-oxo- clopidogrel to an active thiol metabolite. Conflicting results have been reported in regard to (1) the association of a common polymorphism of PON1 (Q192R) with reduced rates of coronary stent thrombosis in patients takin...