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Evaluation of the Biological Response to Clopidogrel in Patients With Ischemic Stroke

Information source: Centre Hospitalier Universitaire de Saint Etienne
ClinicalTrials.gov processed this data on August 23, 2015
Link to the current ClinicalTrials.gov record.

Condition(s) targeted: Brain Ischemia; Ischemic Attack

Intervention: Clopidogrel (Drug)

Phase: N/A

Status: Recruiting

Sponsored by: Centre Hospitalier Universitaire de Saint Etienne

Official(s) and/or principal investigator(s):
Jerome VARVAT, MD, Principal Investigator, Affiliation: CHU de Saint-Etienne

Overall contact:
Jerome VARVAT, MD, Phone: (0)477127770, Ext: +33, Email: jerome.varvat@chu-st-etienne.fr


Ischemic stroke (AIC) is the leading cause of non-traumatic disability in adults, the second leading cause of dementia and the third leading cause of death in France. Clopidogrel is one of the recommended first line in the secondary prevention of AIC non cardioembolic origin. However recurrences occur in approximately 9% of patients receiving clopidogrel. Some studies in patients with coronary artery disease have made the connection between these treatment failures and non-biological response to clopidogrel. This non-biological response is found for approximately 30% to 50% of patients. Several mechanisms may explain this non-response. The most accepted mechanism is pharmacokinetic. Indeed, clopidogrel is a prodrug that requires intestinal absorption by P-glycoprotein (PGP) and a transformation by hepatic cytochrome into active metabolites. The genetic polymorphism of proteins involved in these two steps explain the low plasma concentration of active metabolites and thus the low efficacy of clopidogrel in some patients. A new pharmacodynamic hypothesis suggests the involvement of platelet alpha 2-adrenergic receptors. The activation of these receptors potentiates signaling pathway P2Y12 receptor (channel inhibited by clopidogrel) and helps reduce platelet aggregation inhibiting response to clopidogrel.

Clinical Details

Official title: Evaluation of the Biological Response to Clopidogrel in Patients With Ischemic Stroke : Role of Platelet alpha2-adrenergic Receptors

Study design: Observational Model: Case-Only, Time Perspective: Prospective

Primary outcome: adrenergic component of the platelet response

Secondary outcome:



active metabolite of clopidogrel

Genotyping of MDR-1 and P450 2C19

Detailed description: Interest in the biological response to clopidogrel in the AIC is innovative because few data are available in this area. In addition to testing a new pharmacodynamic hypothesis, we also wish to study and compare other measures of platelet function methods in order to be able to use commonly in treatment decisions.


Minimum age: 18 Years. Maximum age: N/A. Gender(s): Both.


Inclusion Criteria:

- Consent signed

- Patients with non-cardioembolic AIC requiring initiation of treatment with

clopidogrel as usual indications

- normal standard biological tests

Exclusion Criteria:

- Need to continue aspirin therapy

- Patients with a recurrence of clopidogrel AIC

- Patient already tacking clopidogrel

- Drugs interfering with the adrenergic system alpha blockers, alpha 2 receptor

agonists (alpha-methyldopa) and alpha2 receptor inhibitors (Mianserin, Mirtazapine, yohimbine)

- Contra indication of clopidogrel and / or any of its excipients

Locations and Contacts

Jerome VARVAT, MD, Phone: (0)477127770, Ext: +33, Email: jerome.varvat@chu-st-etienne.fr

CHU de Saint-Etienne, Saint-etienne 42000, France; Recruiting
Jerome VARVAT, MD, Principal Investigator
Pierre GARNIER, MD, Sub-Investigator
Magali EPINAT, MD, Sub-Investigator
Sandrine ACCASSAT, MD, Sub-Investigator
Additional Information

Starting date: September 2013
Last updated: July 29, 2015

Page last updated: August 23, 2015

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