Clopidogrel in acute coronary syndrome: when, how much, how long?
An important part of the therapy management of acute coronary syndrome (ACS) consists of antiplatelet drugs. Whereas the administration of acetylsalicylic acid (ASA) is well established, the guidelines recommend the additive use of clopidogrel in patients with ACS without persisting ST-elevation. Clopidogrel should be added to ASA as soon as possible in patients with a non-invasive treatment strategy and continued for more than 1 month (class 1A) and up to 9 months (class 1B). In patients for whom a percutaneous coronary intervention (PCI) is planned, an additional loading-dose of 300 mg clopidogrel should be given on top of ASA (100 mg). These recommendations are based on data recently published in the CURE and CREDO trials, which however should be critically discussed: In these trials, an absolute risk reduction of only 2% could be documented by additive use of clopidogrel. The combined endpoint of cardiovascular death, myocardial infarction and stroke is significantly reduced, but there was no improvement taken the individual endpoints alone. In additional, the data for duration of clopidogrel therapy were determined by taken the mean follow-up of these studies. The efficacy of the dual antiplatelet therapy should be discussed in the context of an increased frequency of major bleedings (in total 1%) and should be considered against a reasonable cost effective background. An adequate therapy with clopidogrel in patients presenting ACS should be confirmed by further trials. Until more detailed data are available, the guideline recommendations should be implemented based on of patient's individual risk.