Aspirin Administration in Myocardial Infarction

Recommended Administration Method

• The American Heart Association recommends administering 162-325 mg of non-enteric coated aspirin that should be chewed before swallowing to achieve the fastest onset of antiplatelet effect compared to other oral formulations 1, 2, 3
• The initial dose of 162 mg has Level of Evidence A support, while the 325 mg dose has Level of Evidence C support 2, 3
• European guidelines recommend 150-325 mg orally for the initial dose 4

Loading Dose Specifications

• Non-enteric coated aspirin must be used for the loading dose, as enteric-coated formulations delay absorption and should never be used acutely 4, 5, 2, 3
• Intravenous aspirin (where available in Europe) can be administered at a dose of 250-500 mg IV 4
• Rectal administration of 325 mg can be used as an alternative route when oral administration is not possible 1

Maintenance Dosing After Loading

• The American College of Cardiology recommends continuing with 75-100 mg daily (non-enteric coated preferred) after the initial loading dose 1, 3
• This maintenance dose should be continued indefinitely to minimize bleeding risk while maintaining efficacy 1, 2, 3

Important Considerations

• There is no guideline recommendation or evidence supporting sublingual aspirin administration in myocardial infarction 4, 1, 5, 2, 6
• Never use enteric-coated aspirin for acute loading, as this delays onset of action by hours 4, 5, 3
• Do not assume sublingual administration is equivalent, as there is zero evidence supporting this route 4, 1, 5, 2, 6