Ticagrelor has a pharmacodynamic advantage over clopidogrel in ACS because ticagrelor:

• A Irreversibly blocks the P2Y12 ADP receptor, providing more sustained platelet inhibition
• B Also inhibits the P2Y1 receptor, blocking both ADP-mediated pathways
• C Is a directly acting, reversible P2Y12 inhibitor not requiring hepatic bioactivation, with faster onset and offset ✓
• D Is a prodrug converted by CYP2C19 to its active metabolite more efficiently than clopidogrel

Explanation

Ticagrelor is a cyclopentyltriazolopyrimidine that directly and reversibly binds the P2Y12 receptor without requiring CYP2C19-mediated bioactivation. This gives ticagrelor a faster, more predictable antiplatelet effect and avoids loss of efficacy in CYP2C19 poor metabolisers (who show reduced clopidogrel response). The reversible binding means platelet function recovers faster after discontinuation (~3-5 days vs 7-10 days for clopidogrel, which binds irreversibly after prodrug activation).

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.