OBJECTIVES: For patients with acute coronary syndrome (ACS) treated with percutaneous coronary intervention, 12-month dual antiplatelet (thienopyridine plus aspirin) treatment is recommended. A phase III clinical trial (TRITON) in ACS patients with planned PCI demonstrated superiority of prasugrel versus clopidogrel on the primary composite endpoint (myocardial infarction, stroke, cardiovascular death) but also higher bleeding risk. This model was designed to estimate the impact on the hospital budget of the national health insurance of substituting prasugrel to clopidogrel. METHODS: The budget impact model was based on index and recurrent hospital stays related to cardiovascular and bleeding causes from the economic cohort of TRITON (N=6705) with a mean of 380 days of follow-up. A specific DRG code was attributed to each stay and transcoded to French DRG. A weighted cost was calculated based on public and private French DRG official tariff (2007), including an average cost for stents and intensive care unit costs. In-hospital costs of thyenopyridine use were not included in the analysis. The time horizon was 1-year. Budget impacts were calculated for two groups: A) Patients without history of transient ischemic attack (TIA) and stroke), B) Patients without TIA/stroke and weight>60 kg and <75 years-old. RESULTS: For Group A the costs for all patients for one year were €25,719,447.48 for prasugrel and €26,123,027.37 for clopidogrel, for Group B they were respectively €20,897,133.23€ and €21,096,756.42. Predominant differences were on costs related to recurrent hospital stays (respectively for A: €5,501,347.76 and €6,053,118.09€ ; B: 4,354,983.17 and 4,827,315.74). Substituting prasugrel to clopidogrel would result in daily savings of: A) €0.45 per patient B) 0.46€ per patient. CONCLUSIONS: This budget impact model showed that prevention of recurrent events with prasugrel generates savings that could offset to some extent potential price differences with clopidogrel.