A patient with chest pain receives aspirin in the field. What is the primary rationale for this action?

• A. To relieve anxiety.
• B. To sedate the patient.
• C. To inhibit platelet aggregation and prevent further clot propagation.
• D. To lower cholesterol.

Answer: (C)

The main idea is to reduce clot growth by stopping platelets from sticking together. Aspirin does this by irreversibly inhibiting the COX-1 enzyme in platelets, which lowers the production of thromboxane A2, a chemical that promotes platelet aggregation. Because platelets can’t make new COX-1, this antiplatelet effect lasts for the platelets’ lifetime (about a week). This helps prevent the clot from getting bigger and reduces damage from a suspected heart attack when given early. It doesn’t relieve anxiety, sedate, or lower cholesterol.