Effect of Amlodipine on Anti-platelet Drug Effect in Patients With Coronary Artery Disease

June 5, 2012 updated by: Ruttonjee Hospital

Effect of Amlodipine on Platelet Inhibition by Clopidogrel in Patients With Ischemic Heart Disease- a Prospective Randomized Controlled Trial

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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

Enrollment (Actual)

97

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
      • Hong Kong SAR, China
        • Ruttonjee Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • ischemic heart disease patient, and
  • given loading or maintenance dose of clopidogrel and in need of it for 1 or more month
  • and in need of additional drug for optimal BP control (aim blood pressure <130/90) or angina control.

Exclusion Criteria:

  • existing use of amlodipine
  • thrombocytopenia
  • end stage renal failure
  • allergy to clopidogrel/ amlodipine
  • pregnancy/ lactation
  • strong inhibitor or inducer of cytochrome P450 3A4 enzyme within 7 days before start of the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: non-amlodipine
For patient with suboptimal angina control: anti-anginal agent excluding calcium channel blocker
Drug: Amlodipine
For patient with suboptimal angina control: oral 2.5-10mg daily
Other Names:
  • Norvasc
Drug: Amlodipine
For patient with suboptimal BP control: 2.5-10mg daily po
Other Names:
  • Norvasc
Active Comparator: non - amlodipine
For patient with suboptimal BP control: anti-hypertensive agent excluding calcium channel blocker
Drug: Amlodipine
For patient with suboptimal angina control: oral 2.5-10mg daily
Other Names:
  • Norvasc
Drug: Amlodipine
For patient with suboptimal BP control: 2.5-10mg daily po
Other Names:
  • Norvasc

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Platelet reactivity unit
Time Frame: baseline and 4 th week
Platelet reactivity unit as measured by VerifyNow system
baseline and 4 th week

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage inhibition of platelet activity
Time Frame: baseline and 4th week
Percentage inhibition of platelet activity measured by VerifyNow system
baseline and 4th week

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ruttonjee Hospital

Investigators

  • Principal Investigator: Andrew YW Li, MB, Ruttonjee Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2010

Primary Completion (Actual)

April 1, 2011

Study Completion (Actual)

April 1, 2011

Study Registration Dates

First Submitted

September 15, 2010

First Submitted That Met QC Criteria

September 15, 2010

First Posted (Estimate)

September 16, 2010

Study Record Updates

Last Update Posted (Estimate)

June 6, 2012

Last Update Submitted That Met QC Criteria

June 5, 2012

Last Verified

June 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Aml-Clo-protocol-v1

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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