title: Is a high maintenance dose of clopidogrel suitable for overcoming clopidogrel resistance in patients?
abstract: BACKGROUND
  A double maintenance dose of clopidogrel at 150 mg daily has been suggested as an effective alternative treatment for patients who have clopidogrel resistance.
  
  
  OBJECTIVE
  To determine if a double maintenance dose of clopidogrel can overcome the low drug response rate observed in patients who have clopidogrel resistance while on a 75 mg daily standard maintenance dose of clopidogrel.
  
  
  METHODS
  A retrospective analysis was conducted in South Korean patients who underwent a platelet function test and received a double maintenance dose of clopidogrel at a secondary medical institution between January 2011 and June 2012. The primary endpoint was to assess clopidogrel response using an adenosine diphosphate test after a double maintenance dose of clopidogrel. The secondary endpoint was the presence of factors that could affect response to clopidogrel.
  
  
  RESULTS
  Of 389 patients identified, 77 patients were eligible for this study. Values from the adenosine diphosphate test decreased significantly in 63 patients (82%) after a double maintenance dose of clopidogrel (p < 0.001). A total of 37 patients (48%) overcame clopidogrel resistance. Concurrent disease appeared to be a contributory factor in clopidogrel resistance.
  
  
  CONCLUSIONS
  A double maintenance dose of clopidogrel at 150 mg daily was associated with a reduction in adenosine diphosphate-induced platelet aggregation in South Korean patients who previously exhibited clopidogrel resistance.
authors.affiliation: Department of Pharmacy, Sun Hospital, Daejeon, South Korea.
authors.forename: Ho
authors.initials: H
authors.lastname: Choi
authors.affiliation: Clinical Pharmacy and Evidence Based Practice Research Lab, College of Pharmacy, ChungAng University, Seoul, 156-756, South Korea.
authors.forename: JiHyeon
authors.initials: J
authors.lastname: Ryu
authors.affiliation: Clinical Pharmacy and Evidence Based Practice Research Lab, College of Pharmacy, ChungAng University, Seoul, 156-756, South Korea.
authors.forename: Heenam
authors.initials: H
authors.lastname: Seo
authors.affiliation: College of Pharmacy, Woosuk University, Wonju-gun, South Korea.
authors.forename: MinKu
authors.initials: M
authors.lastname: Kang
authors.affiliation: Clinical Pharmacy and Evidence Based Practice Research Lab, College of Pharmacy, ChungAng University, Seoul, 156-756, South Korea. eykimjcb777@cau.ac.kr.
authors.forename: Eunyoung
authors.initials: E
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077144:Clopidogrel; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000494:pharmacology*; D012189:Retrospective Studies; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine
keywords: Clopidogrel resistance; High maintenance dose; South Korea