Registered Cardiovascular Invasive Specialist (RCIS) Practice Test

Aspirin acts by inhibiting the action of which compound?

1. Thromboxane

2. Arachidonic Acid

3. Cyclooxygenase

4. Phospholipase A2

The correct answer is: Arachidonic Acid

Aspirin primarily acts by inhibiting the action of cyclooxygenase (COX), which is an enzyme involved in the conversion of arachidonic acid into thromboxane and prostaglandins. By inhibiting COX, aspirin effectively decreases the formation of these compounds, particularly thromboxane A2, which plays a significant role in platelet aggregation and vasoconstriction. This inhibition is crucial for its therapeutic effects, especially in preventing cardiovascular events, as it reduces the ability of platelets to clump together. Arachidonic acid itself is a precursor and not directly the compound that aspirin inhibits; thus, while aspirin acts on pathways involving arachidonic acid, it targets the enzyme that processes this compound rather than the compound itself. In summary, the mechanism through which aspirin operates centers around the inhibition of cyclooxygenase, leading to decreased thromboxane production and ultimately affecting platelet function.