2012 Drugs that promote or inhibit coagulation

Mechanism of action

• CLOPIDOGREL, PRASUGREL and TICLOPIDINE are irreversible ADP receptor antagonists, which inhibit ADP-induced platelet aggregation by preventing activation of IIb/IIIa receptor (i.e., don't block receptor itself, unlike GPIIb/IIIb antagonists)

Pharmacokinetics

• maximal effect observed only after several days of treatment - prolonged bleeding times persist for several days after therapy

Therapeutic Uses

• recommended for patients that don't tolerate aspirin

• standard practice involves administration in patients receiving a coronary stent

Adverse Effects

• CLOPIDOGREL has fewer side effects than TICLOPIDINE

• 10-50% of patients experience bleeding, nausea, diarrhea, rash

• 1% severe leukopenia

• very rarely thrombotic thrombocytopenic purpura (TTP)

• General Mechanisms
• COX inhibitors
• GPIIb/IIIa antagonists
• ADP receptor antagonists
• Dipyridamole