List the antiplatelet agents and outline their mechanisms of action, adverse effects, mode of
elimination and duration of action.

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College Answer

Most candidates did reasonably well by including aspirin, ADP receptor blockade and glycoprotein
2b/3a blockade in their answers. The best approach to answer this type of question was to use a
table with each anti-platelet agent within a column and headings for the rows such as mechanisms
of action, adverse effects, mode of elimination and duration of action.
Common omissions included the irreversibility of the blockade of the platelet function by many of
these agents, renal toxicity and bronchospasm as side effects of aspirin, bone marrow toxicity of
ADP receptor blockers, and dipyridamole as an anti-platelet agent. Some candidates classified
clopidogrel as a glycoprotein 2b/3a blocker incorrectly and thought clopidogrel has a relative short
duration of action on platelet function because of its half-life. Clopidogrel as a prodrug requiring
activation by cytochrome P450 and hence significant potential drug interactions were not
mentioned by any candidates.
Syllabus: J2a,2d
References: Goodman and Gillman, The Pharmacological basis of therapeutics Chp 55