Switching patients from clopidogrel to prasugrel in acute coronary syndrome: impact of the clopidogrel loading dose on platelet reactivity. 

 -  2014 
<br/><br/> BACKGROUND: Patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) commonly receive a clopidogrel LD prior to angiography. Switching these patients to prasugrel may be desirable because higher platelet inhibition is expected.  CONCLUSIONS: Platelet reactivity with prasugrel 60mg added to a clopidogrel 600-mg LD was not significantly different compared with prasugrel 60mg alone in ACS patients undergoing PCI.Copyright © 2014, Wiley Periodicals, Inc.  METHODS: In this open-label, multicenter, nonrandomized trial, 75 patients were categorized into 2 treatment strategies: Those who received a clopidogrel 600-mg LD and received a reloading dose of prasugrel 60mg (clopidogrel/prasugrel group) and those who did not receive a clopidogrel LD and received a prasugrel 60-mg LD (prasugrel group). Platelet reactivity was assessed using VerifyNow P2Y12 reaction units (PRU) and Platelet Reactivity Index vasodilator-stimulated phosphoprotein phosphorylation (PRI-VASP) at 3 different times: at the sheath insertion prior to prasugrel LD, 4hours after prasugrel LD, and at discharge.  OBJECTIVES: The present study aimed to assess the pharmacodynamic response of a prasugrel 60-mg loading dose (LD) alone compared with prasugrel 60mg added to clopidogrel 600mg.  RESULTS: Four hours after prasugrel LD, platelet reactivity did not differ between the clopidogrel/prasugrel group and the prasugrel group according to the VerifyNow assay (median PRU 23 [5-71] vs. 54 [5-91], respectively; P=0.18) and the VASP assay (median PRI 8.67 [4.51-16.85] versus 8.03 [4.82-21.72], respectively; P=1.0). No significant differences in PRU and PRI were observed at discharge. Few bleeding events were reported without any significant differences between the 2 groups. 
<br/><br/><br/>English 
<br/><br/><label>ISSN: </label>0896-4327 
<br/><br/><label>Subjects--Topical Terms: </label><br/>*Acute Coronary Syndrome/th [Therapy]<br/>*Platelet Activation/de [Drug Effects]<br/>*Platelet Aggregation Inhibitors/ad [Administration & Dosage]<br/>*Platelet Aggregation/de [Drug Effects]<br/>*Prasugrel Hydrochloride/ad [Administration & Dosage]<br/>*Ticlopidine/aa [Analogs & Derivatives]<br/>Dose-Response Relationship, Drug<br/>Female<br/>Humans<br/>Male<br/>Middle Aged<br/>Percutaneous Coronary Intervention<br/>Ticlopidine/ad [Administration & Dosage]
<br/><br/><label>Subjects--Geographic Terms: </label><br/>MedStar Washington Hospital Center
<br/><br/><label>Index Terms--Function: </label><br/>Clinical Trial<br/>Journal Article<br/>Multicenter Study<br/>Research Support, Non-U.S. Gov't