Nastaran Ostad, BScPharm, PharmD Candidate, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON.
Glen J. Pearson, BSc, BScPharm, PharmD, FCSHP, Associate Professor of Medicine, Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB.

Dual antiplatelet therapy (DAT) with acetylsalicylic acid and a thienopyridine agent (clopidogrel) as secondary prevention for patients with atherosclerotic coronary artery disease has been proven effective in those with unstable angina or acute coronary syndromes and following a percutaneous coronary intervention. At present, detailed guidelines provide specific guidance to clinicians regarding which patients to treat, the specific safe and effective combination regimen to use, and the appropriate duration of DAT. This evidence applies to the prevention of cardiovascular events in older adults; however, special considerations should be undertaken when using DAT in older adults due to their overall increased propensity for bleeding complications and potential concomitant medication use for comorbid conditions. This article provides an overview of the evidence for DAT, with a focus on treating older adults.
Key words: cardiovascular protection, clopidogrel, acetylsalicylic acid, acute coronary syndromes, coronary stenting.

Sheri L. Koshman, BScPharm, ACPR, PharmD, Assistant Professor of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB.
Glen J. Pearson, BSc, BScPhm, PharmD, FCSHP, Associate Professor of Medicine; Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB.

Antiplatelet agents are the cornerstone of secondary prevention for patients who present with an ischemic stroke or transient ischemic attack (TIA). At present, monotherapy with acetylsalicylic acid (ASA) or clopidogrel or the combination regimen of ASA plus extended-release dipyridamole are recommended as first-line options in the stroke prevention guidelines. The combination of ASA and clopidogrel is not routinely recommended for secondary stroke prevention, since it has been shown to offer no therapeutic advantage and an increased risk of bleeding. The clear answer as to whether one or two antiplatelet agents are better for the secondary prevention of ischemic stroke events in older adults depends upon the combination of agents, as well as the monotherapy comparator.
Key words: stroke prevention, clopidogrel, acetylsalicylic acid, dipyridamole, antiplatelet agents.

The accredited CME learning activity based on this article is offered under the auspices of the CE department of the University of Toronto. Participating physicians are entitled to one (1) MAINPRO-M1 credit by completing this program, found online at www.geriatricsandaging.ca/cme.htm

L. Creed Pettigrew, MD, MPH, Professor of Neurology, Director, Stroke Program, Sanders-Brown Center on Aging, University of Kentucky College of Medicine, Lexington, KY, USA.

Stroke is the most common life-threatening neurological disease and is the fourth leading cause of death among adult Canadians. Aspirin is the most frequently prescribed antithrombotic drug to prevent stroke but may not be a suitable choice in older patients who have already had stroke symptoms despite its use, or cannot tolerate its side effects. For these patients, clopidogrel or the combination of low-dose aspirin with extended release (ER) dipyridamole should be considered for prevention of stroke. This review will compare the relative benefits of aspirin, clopidogrel, and low-dose aspirin/ER-dipyridamole in geriatric patients at risk for stroke.

Key words: stroke, myocardial infarction, aspirin, clopidogrel, dipyridamole.

Shechar Dworski, MSc

Aspirin has been the traditional drug of choice for preventing cardiovascular events in cerebrovascular, cardiovascular, and peripheral vascular disease. However, many recent studies comparing aspirin to ticlopidine and clopidogrel in terms of efficacy and side effects, have produced results which favor these new antiplatelet drugs. Clopidogrel is the newer of the two drugs, and consequently, fewer studies have been done with it. Still, clopidogrel has shown promise as an alternative to ticlopidine; it is safer and has similar efficacy. However, studies are lacking to show that clopidogrel works equally well in all possible clinical situations, whereas ticlopidine's effectiveness has been proven in settings such as post-coronary stent insertion. Nevertheless, studies done with clopidogrel have shown it to be useful in many instances, such as secondary prevention after an initial cerebrovascular (TIA/ stroke) event. Most studies compare the two drugs against aspirin, but not directly against each other. Even so, it has become clear that clopidogrel produces fewer side effects, and is safer than ticlopidine. This article will present some of the information available about these two drugs to help the reader decide which antiplatelet agent to use.