title: Early and late effects of clopidogrel in patients with acute coronary syndromes.
abstract: BACKGROUND
  The risk of ischemic events is high, both early and late after acute coronary syndromes (ACS). We examine the benefits and risks associated with the use of adding clopidogrel to aspirin within the first 30 days and later (31 days to 12 months) in 12 562 patients with ACS.
  
  
  RESULTS
  A total of 12 562 ACS patients were randomized to receive clopidogrel (300 mg initially followed by 75 mg/d) or placebo for 3 to 12 months. The proportion of patients experiencing cardiovascular death, myocardial infarction, or strokes (primary outcome) at 30 days was 5.4% in the placebo group and 4.3% in the active group (relative risk 0.79, 95% CI 0.67 to 0.92). Beyond 30 days, the corresponding rates were 6.3% versus 5.2% (relative risk 0.82, 95% CI 0.70 to 0.95). There was no significant excess in life-threatening bleeds in each period (0.97% versus 1.28%, relative risk 1.32, 95% CI 0.95 to 1.84 for 0 to 30 days; 0.83% versus 0.91%, relative risk 1.09, 95% CI 0.75 to 1.59 for 31 days to 12 months). Further subdivision of the early data indicates benefits within 24 hours with consistently lower rates of the primary outcome in combination with refractory or severe ischemia.
  
  
  CONCLUSIONS
  Clopidogrel reduces the risk of ischemic vascular events, with the benefits emerging within 24 hours of initiation of treatment and continuing throughout the 12 months (mean 9 months) of the study.
authors.affiliation: Population Health Research Institute and Division of Cardiology, McMaster University, Hamilton, Canada. yusufs@mcmaster.ca
authors.forename: Salim
authors.initials: S
authors.lastname: Yusuf
authors.forename: Shamir R
authors.initials: SR
authors.lastname: Mehta
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Gersh
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Commerford
authors.forename: Mel
authors.initials: M
authors.lastname: Blumenthal
authors.forename: Andrzej
authors.initials: A
authors.lastname: Budaj
authors.forename: Thomas
authors.initials: T
authors.lastname: Wittlinger
authors.forename: Keith A A
authors.initials: KA
authors.lastname: Fox
mesh_terms: D000208:Acute Disease; D000789:Angina, Unstable / Q000188:drug therapy* / Q000401:mortality; D001241:Aspirin / Q000627:therapeutic use; D000077144:Clopidogrel; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D017202:Myocardial Ischemia / Q000453:epidemiology; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D018570:Risk Assessment; D055502:Secondary Prevention; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control; D013577:Syndrome; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin