BACKGROUND: Sulfonylureas have been linked to an increased cardiovascular risk by inhibition of myocardial preconditioning. Whether individual sulfonylureas affect outcomes in diabetic patients after emergent percutaneous coronary intervention for myocardial infarction is unknown. METHODS: All Danish patients receiving glucose-lowering drugs admitted with myocardial infarction between 1997 and 2006 who underwent emergent percutaneous coronary intervention were identified from national registers. Multivariable Cox proportional hazards models were used to analyze the risk of cardiovascular mortality and morbidity associated with sulfonylureas. RESULTS: A total of 926 patients were included and 163 (17.6%) patients died during the first year of which 155 (16.7%) were cardiovascular deaths. The most common treatment was sulfonylureas which were received by 271 (29.3%) patients, and 129 (13.9%) received metformin. Cox proportional hazard regression analyses adjusted for age, sex, calendar year, comorbidity and concomitant pharmacotherapy showed an increased risk of cardiovascular mortality (hazard ratio [HR] 2.91, 95% confidence interval [CI] 1.26-6.72 ; p=0.012), cardiovascular mortality and nonfatal myocardial infarction (HR 2.69 , 95% CI 1.21-6.00; p=0.016), and all-cause mortality (HR 2.46, 95% CI 1.11-5.47; p=0.027), respectively, with glyburide compared to metformin. CONCLUSIONS: Glyburide is associated with increased cardiovascular mortality and morbidity in patients with diabetes mellitus undergoing emergent percutaneous coronary intervention after myocardial infarction. Early reperfusion therapy is the mainstay in modern treatment of myocardial infarction and the time may have come to discard glyburide in favour of sulfonylureas that do not appear to confer increased cardiovascular risk.