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

Summary

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.

Timeline

Start

2010-07

Primary completion

2011-04

Completion

2011-04

Publications

• Li AY, Ng FH, Chan FK, Tunggal P, Chan K, Lau YK. Effect of amlodipine on platelet inhibition by clopidogrel in patients with ischaemic heart disease: a randomised, controlled trial. Heart. 2013 Apr;99(7):468-73. doi: 10.1136/heartjnl-2012-302801. Epub 2012 Oct 31.

Drugs

Indications