Clopidogrel Resistance and the Possibility of Its Affection

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00839345
Expanded Access Status : Temporarily not available
First Posted : February 9, 2009
Last Update Posted : February 10, 2009
Information provided by:
Charles University, Czech Republic

Brief Summary:
The purpose of the study is to determine, whether the resistance to clopidogrel could be affected by higher doses of this drug, or by replacement of clopidogrel with another ADP-antagonist ticlopidine.

Condition or disease Intervention/treatment
Coronary Artery Disease Drug: clopidogrel

Detailed Description:
Patients after percutaneous coronary intervention (PCI) with stent implantation have to be treated by dual antiplatelet therapy, which standard part represents clopidogrel. The response to clopidogrel in population exhibits wide interindividual variability. According to some recent works, patients with clopidogrel resistance are in higher risk for recurrence of myocardial infarction in comparison with the patients with sufficient clopidogrel effectiveness. The treatment of clopidogrel resistance is still unknown. Our project should contribute to the better understanding of the clinical impact of clopidogrel resistance and its genetical determination. We will test the hypothesis, whether the clopidogrel resistance could be influenced by higher dose of this drug or by replacement to ticlopidine (ADP antagonist with different biotransformation in the liver). Therefore, 500 pts. will be tested to clopidogrel resistance. We expect 5-10% of resistent pts. This pts. will be treated by higher dose (150mg or 225mg/day) with repeated tests of clopidogrel effectiveness after each dose enhancement. If 225mg/day will be insufficient, clopidogrel will be replaced by ticlopidine with repeated test. We expect, that better definition of clinical and and genetic correlate of clopidogrel resistance will improve our knowledge of this disorder. Nevertheless, the achievement of sufficient effect of clopidogrel in some still resistant patients will lead to the improvement of the treatment

Study Type : Expanded Access
Official Title: Resistance to Antiplatelet Agents, Its Etiology and the Possibility of Its Affection

Intervention Details:
  • Drug: clopidogrel
    The intervention will involve the change of dosage or change of drug. The traditional maintenance dose of clopidogrel is 75 mg per day. We will test in non-responders to this classical dose higher doses up to 225mg per day. In patients,who will not respond to this 3times higher dose,clopidogrel will be replaced by ticlopidine.
    Other Name: Plavix

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Ages Eligible for Study:   18 Years to 90 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All

Inclusion Criteria:

  • written informed consent
  • coronary artery disease verified by coronary angiography
  • percutaneous coronary intervention with stent implantation
  • standard indication for dual antiplatelet therapy

Exclusion Criteria:

  • scheduled surgical revascularization by aortocoronary bypass
  • insufficient cooperation of the patient
  • coagulopathy in history with a higher risk of bleeding
  • life expectancy shorter than 1 year
  • severe anemia with hemoglobin level< 10,0 g/dl
  • platelet count < 100,000)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00839345

Czech Republic
Cardiocenter, Dept. Of Cardiology, Charles University Hospital
Prague, Czech Republic, 10034
Sponsors and Collaborators
Charles University, Czech Republic

Responsible Party: Pavel Osmancik, Charles University, Czech republic Identifier: NCT00839345     History of Changes
Other Study ID Numbers: CLO-OSM-01
First Posted: February 9, 2009    Key Record Dates
Last Update Posted: February 10, 2009
Last Verified: February 2009

Keywords provided by Charles University, Czech Republic:

Additional relevant MeSH terms:
Coronary Artery Disease
Myocardial Ischemia
Coronary Disease
Heart Diseases
Cardiovascular Diseases
Arterial Occlusive Diseases
Vascular Diseases
Platelet Aggregation Inhibitors
Purinergic P2Y Receptor Antagonists
Purinergic P2 Receptor Antagonists
Purinergic Antagonists
Purinergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Fibrinolytic Agents
Fibrin Modulating Agents
Cytochrome P-450 CYP2C19 Inhibitors
Cytochrome P-450 Enzyme Inhibitors
Enzyme Inhibitors