Which statement about Clopidogrel is correct?

• A. Reversible
• B. Administered IV
• C. Onset 2-4 hours
• D. Not used before PCI

Answer: (C)

Clopidogrel works as an oral prodrug that, after hepatic activation, irreversibly blocks the platelet P2Y12 receptor, so its antiplatelet effect lasts for the life of the platelet. Because it requires metabolic activation and is given by mouth, there is a delay before the effect appears. After a loading dose, antiplatelet activity begins within about 2 hours, with clinically meaningful effect typically evident by 2–4 hours. It is routinely used before PCI as part of dual antiplatelet therapy to reduce thrombotic risk, so the statement that it is not used prior to PCI is not correct.