With potent analgesic properties, perceived hemodynamic benefits and limited alternatives, opiates are the analgesic mainstay for acute coronary syndrome (ACS) patients reporting peri-procedural pain or nitrate-resistant chest pain. However, large observational studies suggest that opiate administration during ACS may result in adverse cardiovascular outcomes. Complimenting this, a number of recent mechanistic studies have demonstrated delayed and attenuated effects of oral dual anti-platelet therapy (DAPT) on platelet inhibition endpoints among subjects receiving intravenous morphine. These studies support the hypothesis that morphine delays the gastrointestinal absorption of DAPT medications. However, no data exist on the impact of intravenous fentanyl, a systemic opioid analgesic routinely administered during percutaneous coronary intervention (PCI) procedures, on the platelet inhibition effects of DAPT. The investigators hypothesize that, similar to morphine, fentanyl administered at the time of PCI will reduce and delay the effect of DAPT on platelet function. As such, the primary aim of this study is to test the impact of intravenous fentanyl on residual platelet reactivity by randomizing patients undergoing PCI to a strategy of peri-procedural benzodiazepine plus non-systemic local analgesia or to the current standard of benzodiazepine plus intravenous fentanyl. Given the critical need for rapid and robust inhibition of platelet function during PCI, this trial has true potential to change clinical practice, particularly if the investigators demonstrate reduced DAPT absorption and elevated residual platelet reactivity among patients receiving fentanyl during PCI.