title: Comparison between the effect of omeprazole and rabeprazole on the antiplatelet action of clopidogrel.
abstract: BACKGROUND
  Emerging data suggests that several proton pump inhibitors (PPIs), including omeprazole, might interfere with the antiplatelet action of clopidogrel. However, there is a lack of data for rabeprazole. This study aimed to investigate and compare the impact of omeprazole and rabeprazole on the antiplatelet action of clopidogrel among patients with coronary artery disease (CAD).
  
  
  RESULTS
  A prospective, randomized, open-labeled study was conducted among 87 CAD patients receiving clopidogrel and aspirin. Forty three and 44 patients were randomized to receive omeprazole 20 mg and rabeprazole 20 mg once daily, respectively, for at least 2 weeks. Adenosine 5-diphosphate 20 µmol/L-induced platelet aggregation was performed before and after PPIs treatment. Mean maximal platelet aggregation (MPA) before and after PPIs treatment of both groups were compared. At baseline, there were no significant differences in the mean MPA between the omeprazole and rabeprazole groups (40.68 ± 18.82% vs 36.42 ± 21.39%; P=0.326). After a 2-week treatment with PPIs, the mean MPA in both groups significantly increased from baseline and there were no differences between the omeprazole and rabeprazole groups (55.73 ± 19.66% vs 48.46 ± 18.80%; P=0.141).
  
  
  CONCLUSIONS
  Both omeprazole and rabeprazole decreased the antiplatelet effect of clopidogrel. Use of these agents resulted in a similar degree of interference on clopidogrel's action, as measured by ADP-induced platelet aggregation.
authors.affiliation: Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Suksiri
authors.initials: S
authors.lastname: Siriswangvat
authors.forename: Nakarin
authors.initials: N
authors.lastname: Sansanayudh
authors.forename: Surakit
authors.initials: S
authors.lastname: Nathisuwan
authors.forename: Duangchit
authors.initials: D
authors.lastname: Panomvana
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000008:administration & dosage* / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000368:Aged; D001241:Aspirin / Q000627:therapeutic use; D000077144:Clopidogrel; D003324:Coronary Artery Disease / Q000188:drug therapy*; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000008:administration & dosage / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D064750:Rabeprazole; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D016896:Treatment Outcome
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D004791:Enzyme Inhibitors; D010975:Platelet Aggregation Inhibitors; D064750:Rabeprazole; D000244:Adenosine Diphosphate; D000077144:Clopidogrel; D009853:Omeprazole; D013988:Ticlopidine; D001241:Aspirin