title: Omeprazole affects clopidogrel efficacy but not ischemic events in patients with acute coronary syndrome undergoing elective percutaneous coronary intervention.
abstract: BACKGROUND
  Omeprazole, usually used in the antiplatelet therapy during percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS), has been reported to increase ischemic events in retrospective studies. However, other clinical trials gave paradoxical results. The aim of this study was to assess the effects of omeprazole on clopidogrel efficacy and clinical events.
  
  
  METHODS
  All patients (n = 172) received aspirin (loading dose 300 mg and maintenance dose 100 mg/d) and clopidogrel (loading dose 600 mg and maintenance dose 75 mg/d) during the therapy. They were randomized to receive omeprazole (20 mg/d) or placebo for 30 days. Residual platelet activities in the adenosine 5'-diphosphate (ADP) pathway were detected on the fifth day after PCI with thrombelastography (TEG)-mapping. The clinical events were recorded after one month.
  
  
  RESULTS
  According to the five levels of platelet activities, the frequency distributions of the inhibition rates were significantly different (P = 0.0062). However, no significant change was seen in the distribution among the highest or the lowest inhibiting levels (> 95% and < 30% inhibition rate). And there were no significant differences (P > 0.05) in events incidence, while gastro-intestinal bleeding decreased in co-administration of omeprazole.
  
  
  CONCLUSIONS
  Omeprazole significantly blunts clopidogrel efficacy while not exacerbates ischemic events in ACS undergoing PCI. Omeprazole even can decrease gastro-intestinal bleeding in those patients.
authors.affiliation: Department of Cardiology, Chinese People's Liberation Army General Hospital, Beijing 100853, China. rainbowren301@yahoo.com.cn
authors.forename: Yi-hong
authors.initials: YH
authors.lastname: Ren
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.forename: Yun-dai
authors.initials: YD
authors.lastname: Chen
authors.forename: Lian
authors.initials: L
authors.lastname: Chen
authors.forename: Hong-bin
authors.initials: HB
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhi-jun
authors.initials: ZJ
authors.lastname: Sun
authors.forename: Jin-song
authors.initials: JS
authors.lastname: Chen
authors.forename: Ting-ting
authors.initials: TT
authors.lastname: Huang
authors.forename: Yu-song
authors.initials: YS
authors.lastname: Guo
authors.forename: Yong-jin
authors.initials: YJ
authors.lastname: Xie
authors.forename: Chun-ya
authors.initials: CY
authors.lastname: Wang
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood / Q000188:drug therapy* / Q000473:pathology / Q000628:therapy*; D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D001241:Aspirin / Q000627:therapeutic use; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000627:therapeutic use*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D009853:Omeprazole; D013988:Ticlopidine; D001241:Aspirin