Prasugrel is a new thienopyridine alternative to clopidogrel and is now listed as an option in the 2011 ACC/AHA Non-STEMI ACS Guidelines. Studies comparing it versus clopidogrel show a slight benefit in terms of adverse cardiac events, but at the expense of a slight increase in bleeding complications. Though the guidelines state no preference between prasugrel vs. clopidogral for NSTEMI ACS patients, prasugrel is finding a role in patients who appear to have a genetic resistance to the effects of clopidogrel (unlikely you'll know this in the ED, but you'll start seeing more patients started on this medication in the outpatient setting).
Prasugrel is contraindicated in patients with a history of TIA or stroke and it should not be given before cath is performed (in contrast, some protocols push for clopidogrel as early as possible, even before cath).
