Pharmacology · single question
Aspirin and clopidogrel both primarily affect which hemostatic parameter?
Show answer and explanation
Correct answer: C. Platelet function/aggregation (bleeding time)
Both are antiplatelet drugs that impair platelet FUNCTION: Aspirin — irreversibly inhibits COX-1 → reduced thromboxane A2 → decreased platelet aggregation. Clopidogrel — irreversibly blocks P2Y12 ADP receptor → decreased aggregation. Standard coagulation tests (PT, aPTT) remain NORMAL. Bleeding time/platelet function analyzer is prolonged.
- A. ❌ aPTT measures the intrinsic coagulation pathway — prolonged by heparin, not antiplatelet drugs.
- B. ❌ Platelet COUNT is not affected — these drugs affect platelet FUNCTION, not production.
- C. ✅ Platelet function/aggregation — both aspirin and clopidogrel specifically impair platelet aggregation.
- D. ❌ PT/INR measures the extrinsic pathway — prolonged by warfarin, liver disease; not by antiplatelet drugs.