Which of the following is the aspirin dose and its use in this emergency protocol?

• A. 100 mg orally; Used for chest pain.
• B. 150 mg orally; Used for stroke.
• C. 200 mg orally; Used for fever.
• D. 300 mg orally; Used for myocardial infarction.

Answer: (D)

In a suspected myocardial infarction, aspirin is given to prevent further clot formation by inhibiting platelet activity. The most effective approach in an emergency protocol is a single 300 mg dose taken by mouth and chewed. Chewing speeds up absorption through the oral mucosa, allowing a quicker onset of action when time is critical. The drug works by irreversibly inhibiting platelet cyclooxygenase-1, which reduces thromboxane A2 and thus platelet aggregation, helping to limit the size of the infarct and improve outcomes if administered early. The other options propose doses or uses that do not align with the acute MI protocol—lower doses or uses for fever or stroke—so they are not appropriate in this emergency context.