title: Pharmacodynamic Assessment of Platelet Reactivity After a Loading Dose of Prasugrel or Clopidogrel in Patients With ST-Segment Elevation Myocardial Infarction.
abstract: Few studies have compared the platelet reactivity of prasugrel and clopidogrel in the acute phase of ST-segment elevation myocardial infarction (STEMI).
  
  
  
  Primary percutaneous coronary intervention (PCI) was performed in 78 patients with STEMI within 12 h of onset. Patients were randomly assigned to receive a Japanese standard loading dose of prasugrel 20 mg or clopidogrel 300 mg. Platelet reactivity was serially assessed using the VerifyNow-P2Y12 assay, the results of which were expressed as P2Y12-reaction-units (PRU). PRU values were significantly lower in the prasugrel group (n=38) than in the clopidogrel group (n=40) at 3 h, 24 h, and 14 days after loading (191±101 vs. 271±50, 147±80 vs. 261±57, and 171±67 vs. 221±70, respectively, P<0.05), although the PRU levels at baseline (231±57 vs. 237±58, P=0.65) and 1 h after loading (282±65 vs. 291±62, P=0.54) were similar. As compared with the baseline values, the PRU levels at 1, 3 and 24 h after clopidogrel loading were significantly higher (respectively, P<0.05), whereas only the PRU at 1 h after prasugrel was elevated (P<0.001).
  
  
  
  In Japanese patients with STEMI who undergo primary PCI, prasugrel provides stronger platelet inhibition than clopidogrel from 3 h after loading, whereas platelet reactivity remained elevated within 24 h after clopidogrel loading. (Circ J 2016; 80: 2520-2527).
authors.affiliation: Division of Cardiology, Yokohama City University Medical Center.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ichikawa
authors.forename: Kengo
authors.initials: K
authors.lastname: Tsukahara
authors.forename: Yugo
authors.initials: Y
authors.lastname: Minamimoto
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kimura
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Matsuzawa
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Maejima
authors.forename: Noriaki
authors.initials: N
authors.lastname: Iwahashi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hibi
authors.forename: Masami
authors.initials: M
authors.lastname: Kosuge
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ebina
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kimura
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention; D015539:Platelet Activation / Q000187:drug effects*; D000068799:Prasugrel Hydrochloride / Q000008:administration & dosage / Q000493:pharmacokinetics; D000072657:ST Elevation Myocardial Infarction / Q000097:blood / Q000601:surgery; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: D000077144:Clopidogrel; D000068799:Prasugrel Hydrochloride; D013988:Ticlopidine