Clinical Pharmacology and Therapeutics 2014-12-01

Clopidogrel bioactivation and risk of bleeding in patients cotreated with angiotensin-converting enzyme inhibitors after myocardial infarction: a proof-of-concept study.

K E Kristensen, H-J Zhu, X Wang, G H Gislason, C Torp-Pedersen, H B Rasmussen, J S Markowitz, P R Hansen

Index: Clin. Pharmacol. Ther. 96(6) , 713-22, (2014)

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Abstract

Clopidogrel is an oral antiplatelet prodrug, the majority of which is hydrolyzed to an inactive metabolite by hepatic carboxylesterase 1 (CES1). Most angiotensin-converting enzyme inhibitors (ACEIs) are also metabolized by this enzyme. We examined the effects of ACEIs on clopidogrel bioactivation in vitro and linked the results with a pharmacoepidemiological study. In vitro, ACEIs inhibited CES1-mediated hydrolysis of a model substrate, and trandolapril and enalapril increased formation of clopidogrel active metabolite. In 70,934 patients with myocardial infarction, hazard ratios for clinically significant bleeding in ACEI-treated patients cotreated with or without clopidogrel were 1.10 (95% confidence interval (CI): 0.97-1.25, P = 0.124) and 0.90 (95% CI: 0.81-0.99, P = 0.025), respectively, as compared with patients who did not receive ACEIs. This difference was statistically significant (P = 0.002). We conclude that cotreatment with selected ACEIs and clopidogrel may increase the risk of bleeding. Combination of in vitro and pharmacoepidemiological studies may be a useful paradigm for assessment of drug-drug interactions.