January 4, 2012
Volume 7 - Issue 1    

DynaMed Weekly Update

For the week ending December 30, 2011 

Last week 536 articles were evaluated via DynaMed's Systematic Literature Surveillance and 196 were added to DynaMed content. 

Based on the editors' criteria of selecting "articles most likely to change clinical practice," one article of significant interest was selected for the DynaMed Weekly Update.

Feature Article

CYP2C19 Genotype May Not Increase Risk of Cardiovascular Events in Patients Taking Clopidogrel

Clopidogrel (Plavix) comes with a boxed warning, issued by the FDA in 2010, suggesting genetic testing for the CYP2C19 genotype prior to use. The warning was based on data suggesting that slow metabolism of the drug due to the genotype was associated with decreased efficacy and increased risk of cardiovascular events. The American Heart Association and the American College of Cardiologists issued a consensus statement disputing the warning for insufficient evidence to recommend routine screening (J Am Coll Cardiol. 2010 Jul 20;56(4):321). A new systematic review of 32 studies appears to support this dissenting view.


The review included data from 42,016 patients (mean age 63 years) with acute coronary syndrome or stable coronary heart disease. There was a total of 3,545 cardiovascular disease events. In analysis of 26 observational studies, presence of ≥ 1 CYP2C19 allele was associated with increased risk of cardiovascular disease events in patients taking clopidogrel (relative risk 1.18, 95% CI 1.09-1.28). However, these results appear to have been due to data from small studies and in an analysis limited to 4 studies with at least 200 events (10,570 patients), there was no significant difference in event rates between carriers and non-carriers.


In a subgroup meta-analysis of 11,012 patients with the CYP2C19 genotype from 4 randomized trials, clopidogrel was associated with reduced risk of cardiovascular events compared to placebo (risk ratio 0.8, 95% CI 0.72-0.89). This risk reduction was similar to that found in the overall analysis disregarding genotype (risk ratio 0.84, 95% CI 0.79-0.89). The risk of major bleeding was increased with clopidogrel in both subgroup and overall analyses (level 2 [mid-level] evidence)(JAMA 2011 Dec 28;306(24):2704).


For more information, see the Clopidogrel topic in DynaMed.

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About DynaMed Weekly Update

Prepared by the clinician members of the DynaMed Editorial Team, DynaMed Weekly Update is a compilation of one to five articles selected from DynaMed's Systematic Literature Surveillance as articles most likely to change clinical practice.

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CME Information


0.25 AMA PRA Category I Credit(s)™
Family Physicians: 0.25 Prescribed credits
Nurse Practitioners: 0.25 Contact hours
Release Date: January 4, 2012 
Expiration Date: January 4, 2013
Estimated Completion Time:
15 minutes
There is no fee for this activity.

To Receive Credit 
In order to receive your certificate of participation, you should read the information about this activity, including the disclosure statements, review the entire activity, take the post-test, and complete the evaluation form. You may then follow the directions to print your certificate of participation. To begin, click the CME icon at the end of the article.

Program Overview

Learning Objectives

Upon successful completion of this educational program, the reader should be able to:
1. Discuss the significance of this article as it relates to your clinical practice.
2. Be able to apply this knowledge to your patient's diagnosis, treatment and management.
Faculty Information
Alan Ehrlich, MD - Assistant Clinical Professor in Family Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA; Deputy Editor, DynaMed, Ipswich, Massachusetts, USA

Michael Fleming, MD, FAAFP - Assistant Clinical Professor of Family Medicine and Comprehensive Care, LSU Health Science Center School of Medicine, Shreveport, Louisiana, USA; Assistant Clinical Professor of Family Medicine, Department of Family and Community Medicine, Tulane University Medical School, New Orleans, Louisiana, USA; Chief Medical Officer, Amedisys, Inc. & Antidote Education Company

Dr. Ehrlich, Dr. Fleming, DynaMed Editorial Team members, and the staff of Antidote Education Company have disclosed that they have no relevant financial relationships or conflicts of interest with commercial interests related directly or indirectly to this educational activity.
No commercial support has been received for this activity.

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ACCME This activity has been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education through the joint sponsorship of Antidote Education Company and EBSCO Publishing. Antidote is accredited by the ACCME to provide continuing medical education for physicians.  Antidote Education Company designates this educational activity for a maximum of 0.25 AMA PRA Category 1 Credits™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

AAFP: This activity, DynaMed Weekly Update 2011, has been reviewed and is acceptable for up to 13 Prescribed credits by the American Academy of Family Physicians. AAFP accreditation begins March 2, 2011. Term of approval is for one year from this date. Each Weekly Update is approved for 0.25 Prescribed credits. Credit may be claimed for one year from the date of each Weekly Update.


AANP: This program is approved for 0.25 contact hour of continuing education by the American Academy of Nurse Practitioners.  

Program ID 1102071S.

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