Clopidogrel

Clopidogrel, which is often prescribed under the brand name Plavix® (clopidogrel bisulfate; produced by Bristol-Myers Squibb and Sanofi-Aventis), is a potent oral antiplatelet agent often used in the treatment of coronary artery disease, peripheral vascular disease, and cerebrovascular disease. more...

Pharmacology

The mechanism of action of clopidogrel is irreversible blockade of the adenosine diphosphate (ADP) receptor on platelet cell membranes. This receptor is named P2Y12 and is important in platelet aggregation, the cross-linking of platelets by fibrin. The blockade of this receptor inhibits platelet aggregation.

Two hours after a single dose of oral Plavix®, platelet inhibition can be demonstrated.

Pregnancy category

Clopidogrel is pregnancy category B. This means that in animal models, there is no risk of adverse effects in doses equivalent to doses that a pregnant female would ingest. The implication is that the medication is probably safe to administer during human pregnancy. It is currently unknown whether clopidogrel is excreted in human breast milk.

Adverse effects

Serious adverse effects that are associated with clopidogrel include:

• Severe neutropenia (Incidence: 5/10,000)
• Thrombotic thrombocytopenic purpura (TTP) (Incidence: 4/1,000,000 patients treated)
• Hemorrhage - The incidence of hemorrhage may be increased by the co-administration of aspirin.
  • Gastrointestinal Hemorrhage (Incidence: 2.0%)
  • Cerebral Hemorrhage (Incidence: 0.1 to 0.4%)

Most consensus-based therapeutic guidelines recommend the use of clopidogrel, over aspirin, in patients requiring antiplatelet therapy but with a history of gastric ulceration due to the lower incidence of gastric ulceration associated with the use of clopidogrel vs aspirin. A recent study has shown that in patients with healed aspirin-induced ulcers, however, patients receiving aspirin plus the proton pump inhibitor esomeprazole had a lower incidence of recurrent ulcer bleeding than patients receiving clopidogrel. (Chan et al., 2005)

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