From the Guidelines
Aspirin should be chewed or crushed rather than swallowed whole during Acute Coronary Syndrome (ACS) because this method of administration leads to faster absorption and quicker antiplatelet effects. The recommended dose is 162-325 mg (typically a single 325 mg tablet or four 81 mg baby aspirin tablets) administered as soon as ACS is suspected 1. Chewing or crushing the tablet allows the medication to be absorbed through the oral mucosa and enter the bloodstream more rapidly than when swallowed whole, which requires dissolution in the stomach first. This faster absorption is critical in ACS because platelets are actively forming clots in the coronary arteries, and the sooner aspirin can inhibit platelet aggregation, the better chance of limiting myocardial damage.
The antiplatelet effects begin within minutes when aspirin is chewed, compared to up to 30 minutes when swallowed whole. Key considerations for aspirin administration in ACS include:
- Using a non-enteric coated formulation for faster absorption
- Administering a loading dose of 162-325 mg as soon as possible
- Continuing with a daily maintenance dose of 75-100 mg 1
- Ensuring the patient chews the aspirin when possible to achieve rapid onset of action
After the initial dose, patients should continue taking aspirin daily (typically 75-100 mg) as directed by their healthcare provider as part of their ongoing cardiac care regimen 1. It's also important to note that aspirin therapy administered within the first 24 hours after acute STEMI resulted in a significant reduction in vascular mortality and non-fatal reinfarction 1. Overall, the most recent and highest quality evidence supports chewing or crushing aspirin in ACS to rapidly achieve antiplatelet effects and improve patient outcomes 1.
From the Research
Importance of Aspirin in Acute Coronary Syndrome (ACS)
- Aspirin is recommended for all patients with a suspected acute coronary syndrome (ACS) unless contraindicated 2
- Aspirin is the foundation antiplatelet agent in the management of ACS 3
Administration of Aspirin in ACS
- There is no direct evidence in the provided studies that suggests aspirin should be chewed or crushed in ACS
- However, it is known that chewing or crushing aspirin can help it dissolve more quickly, potentially leading to faster absorption and onset of action
Antiplatelet and Anticoagulation Therapy in ACS
- Dual antiplatelet therapy, including aspirin and a P2Y12 inhibitor (such as clopidogrel, prasugrel, or ticagrelor), is recommended for most patients with ACS 2, 3, 4
- Parenteral anticoagulation with unfractionated heparin, low-molecular-weight heparin, bivalirudin, or fondaparinux is also recommended 2, 4
Management of ACS
- Coronary angiography with percutaneous or surgical revascularization is an important management consideration for patients with ACS 2, 5, 6
- Other management considerations include initiation of dual antiplatelet therapy, parenteral anticoagulation, statin therapy, beta-blocker therapy, and sodium-glucose cotransporter-2 inhibitor therapy 2, 5, 6