The timing of administering aspirin and nitroglycerin in patients with STEMI ECG changes alter patient outcome

Both chewed aspirin and sublingual nitroglycerin are fast acting medications and reach therapeutic levels within a few minutes. Current guidelines for managing acute coronary syndrome (ACS) do not recognize the importance of the order or timing of administering aspirin and nitroglycerin. This retrospective study aimed to examine if there was any benefit to the timing of giving aspirin before or after nitroglycerin in cases of ACS.

From the large National Emergency Medical Services Information System (NEMSIS) 2017 Version database, 2594 patients with acute coronary syndrome were identified (based on chest pain and their ECG finding) that received aspirin plus nitroglycerin in prehospital settings. Based on which medication was given first, the patients were separated in 2 groups: an aspirin-first and a nitroglycerin-first group. The 2246 patients who received aspirin first were further stratified based on the time between administration of aspirin and the first dose of nitroglycerin. The other 348 patients who received nitroglycerin first were similarly stratified.

In patients with STEMI ischemia, giving nitroglycerin 10 min after aspirin dosing (compared to giving them simultaneously) leads to a greater than 20% reduction in need for additional nitroglycerin, a greater than 7% decrease in subjective pain experienced by the patient and reduced need for additional opioids. The aspirin-first group in total, had a 39.6% decrease in subjective pain experience after giving additional nitroglycerin compared to nitroglycerin-first group.

In patients with ACS, this study found that giving nitroglycerin 10 min after aspirin was associated with a reduction in subjective pain scores, as well as a reduced need for additional nitroglycerin or opioids. Future prospective trials examining the timing of aspirin vs. nitroglycerin are needed to confirm these findings.