title: Clopidogrel and the possibility of drug-drug interaction in primary health care.
abstract: BACKGROUND
  Clopidogrel ineffectiveness is a serious problem in antiplatelet therapy. Many factors may contribute to this phenomenon. One of them is clopidogrel drug-drug interaction with CYP2C19 and CYP3A4 enzyme inhibitors. The main goal of this descriptive study was to assess the prevalence of cases of clopidogrel-drug interactions in the primary health care physicians' practices.
  
  
  METHODS
  During 2010-2011, 80 patients receiving clopidogrel antiplatelet therapy from primary care physicians' clinical practices were involved in this study. By using questionnaires and case histories, the following information was collected: Age, gender, clinical diagnoses, and medications used.
  
  
  RESULTS
  IN THE CURRENT STUDY, DRUGS WERE USED THAT COULD POTENTIALLY INFLUENCE THE EFFECT OF CLOPIDOGREL: Omeprazole, lipophilic statins, calcium channel blockers (CCB). There was a different use of the above-mentioned drugs before and after the initiation of the clopidogrel therapy, e.g., 12 (15.0%) and 44 (55.0%) patients used proton pump inhibitors (PPI) before and after the clopidogrel therapy accordingly (P = 0.16; χ (2) = 1.91). However, pantoprazole was recommended more often than other PPI. The use of the potential CYP3A4 inhibitors - lipophilic statins and CCB - was increased after the prescription of clopidogrel too. Concomitant use of statins (mainly atorvastatin) with clopidogrel was observed in 75 (93.8%) patients and the use of CCB (mainly amlodipine) - in 33 (41.3%) patients.
  
  
  CONCLUSIONS
  In the primary health care practices, it is revealed that there is co-medication of clopidogrel with weak CYP3A4 inhibitors, such as lipophilic statins and amlodipine, and with the moderate CYP2C19 inhibitor - omeprazole. The latter co-medication is potentially harmful and it is very important to inform the first care professionals about the opportunity to change omeprazole to pantoprazole, which does not influence clopidogrel biotransformation.
authors.affiliation: Department of Pharmacy, Riga Stradiņš University, Latvia.
authors.forename: Inga
authors.initials: I
authors.lastname: Urtane
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Aitullina
authors.forename: Katrina
authors.initials: K
authors.lastname: Pukite
keywords: Amlodipine; Atorvastatin; Clopidogrel; Drug–drug interaction; Omeprazole
references.citation: Heart. 2010 Feb;96(3):186-9
references.pmid: 19687016
references.citation: Clin Pharmacol Ther. 2011 Jan;89(1):65-74
references.pmid: 20844485
references.citation: Thromb Res. 2011 Oct;128(4):307-16
references.pmid: 21592545
references.citation: Curr Pharm Des. 2006;12(10):1271-80
references.pmid: 16611111
references.citation: Thromb Haemost. 2010 May;103(5):920-5
references.pmid: 20352154
references.citation: Clin Med Insights Cardiol. 2010 Dec 01;4:117-28
references.pmid: 21151850
references.citation: J Am Coll Cardiol. 2011 Jan 25;57(4):409-17
references.pmid: 21251580
references.citation: Clin Pharmacol Ther. 2006 Dec;80(6):565-81
references.pmid: 17178259
references.citation: Eur J Clin Invest. 2012 Mar;42(3):266-74
references.pmid: 21834799
references.citation: Br J Pharmacol. 2010 Sep;161(2):393-404
references.pmid: 20735423
references.citation: Drug Metab Rev. 2002 Feb-May;34(1-2):17-35
references.pmid: 11996009
references.citation: J Am Coll Cardiol. 2008 Oct 28;52(18):1502-17
references.pmid: 19017521
references.citation: Circulation. 2003 Aug 26;108(8):921-4
references.pmid: 12925453
references.citation: J Am Coll Cardiol. 2008 Nov 4;52(19):1557-63
references.pmid: 19007592
references.citation: Future Cardiol. 2011 May;7(3):381-402
references.pmid: 21627478
references.citation: Curr Drug Metab. 2010 Oct;11(8):667-77
references.pmid: 20942779
references.citation: Circ Cardiovasc Interv. 2012 Feb 1;5(1):77-81
references.pmid: 22319066
references.citation: Am J Cardiol. 2003 Aug 1;92(3):285-8
references.pmid: 12888133
references.citation: Drug Saf. 2006;29(9):769-84
references.pmid: 16944963
references.citation: J Am Coll Cardiol. 2005 Apr 19;45(8):1157-64
references.pmid: 15837243
references.citation: Circulation. 2003 Jan 7;107(1):32-7
references.pmid: 12515739