Effect of Amlodipine on Anti-platelet Drug Effect in Patients With Coronary Artery Disease
|ClinicalTrials.gov Identifier: NCT01203696|
Recruitment Status : Completed
First Posted : September 16, 2010
Last Update Posted : June 6, 2012
Clopidogrel can reduce risk of cardiovascular disease by inhibiting platelet aggregation. It is metabolized to an active drug by a liver enzyme. Its efficacy may be measured by blood sampling for platelet activity, analyzed by VerifyNow device. Calcium Channel blocker (CCB) is also commonly used for blood pressure and anginal control in these patients. Dihydropyridine group of calcium channel blocker (e.g. amlodipine) inhibits this enzyme. There are observational studies reporting dihydropyridine CCB reducing clopidogrel effect, but the clinical implication is unclear.
This study test the hypothesis that there is no significant effect of dihydropyridines CCB on clopidogrel response compared with control. After giving consent, patients with suboptimal blood pressure or anginal control will be randomized to receive either dihydropyridine CCB or non-CCB as placebo. These patient will be follow-up in 1 month.
|Condition or disease||Intervention/treatment||Phase|
|Ischemic Heart Disease||Drug: Amlodipine||Phase 4|
Clopidogrel is a pro-drug, which requires hepatic transformation by the cytochrome P450 isoform 3A4 to generate the active metabolite. It inhibits adenosine-5-diphosphate (ADP)-induced platelet aggregation by irreversibly blocking the platelet P2Y12 receptor. However, response to clopidogrel shows wide individual variability, and patients with high on-treatment residual ADP-induced platelet reactivity are at an increased risk of adverse cardiovascular events. Previous study suggest co-administration of CCBs is associated with decreased platelet inhibition by clopidogrel, but these observational studies are confounded by patient's characteristics baseline difference such as proportion of hypertension and diabetes.
The objective of this randomized controlled study is to compare amlodipine with placebo on anti-platelet effect of clopidogrel.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||97 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||None (Open Label)|
|Official Title:||Effect of Amlodipine on Platelet Inhibition by Clopidogrel in Patients With Ischemic Heart Disease- a Prospective Randomized Controlled Trial|
|Study Start Date :||July 2010|
|Actual Primary Completion Date :||April 2011|
|Actual Study Completion Date :||April 2011|
Active Comparator: non-amlodipine
For patient with suboptimal angina control: anti-anginal agent excluding calcium channel blocker
For patient with suboptimal angina control: oral 2.5-10mg daily
Other Name: Norvasc
Active Comparator: non - amlodipine
For patient with suboptimal BP control: anti-hypertensive agent excluding calcium channel blocker
For patient with suboptimal BP control: 2.5-10mg daily po
Other Name: Norvasc
- Platelet reactivity unit [ Time Frame: baseline and 4 th week ]Platelet reactivity unit as measured by VerifyNow system
- Percentage inhibition of platelet activity [ Time Frame: baseline and 4th week ]Percentage inhibition of platelet activity measured by VerifyNow system
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 ClinicalTrials.gov identifier (NCT number): NCT01203696
|Hong Kong SAR, China|
|Principal Investigator:||Andrew YW Li, MB||Ruttonjee Hospital|