Antiplatelet Agents and Anticoagulants PDF

Antiplatelet Agents and Anticoagulants Elizabeth Cohen, PharmD BCPS N6020 Advanced Pharmacology Objectives Review the coagulation cascade, platelet aggregation and clot formation Describe medications which affect hemostasis including dose, mechanism of action and adverse effec...

Antiplatelet Agents and Anticoagulants Elizabeth Cohen, PharmD BCPS N6020 Advanced Pharmacology Objectives Review the coagulation cascade, platelet aggregation and clot formation Describe medications which affect hemostasis including dose, mechanism of action and adverse effects Identify monitoring parameters and contraindications of antiplatelet agents and anticoagulants Compare and contrast anticoagulants Formulate an appropriate anticoagulation regimen given an individual patient case List relevant antidotes Hemostasis Process of maintaining fluidity of the blood, repairing vascular injury, and limiting blood loss while Clotting avoiding vessel occlusion (thrombosis) Bleeding and inadequate perfusion of vital organs Hemostasis: Thrombosis Ischemic Stroke Pulmonary Embolism (PE) Myocardial Infarction (MI) Deep Venous Thrombosis (DVT) Clotting Platelet Adhesion & Aggregation Fibrin Clot Formation Coagulation Cascade Anticoagulation: Monitoring PTT Xa PT/INR Heparin LMWH Coumadin (warfarin) Angiomax Arixtra (bivalirudin), (fondaparinux) Argatroban International Normalized Ratio (INR) Prothrombin time (PT) can vary greatly depending on the lab test and reagents used INR accounts for variability between labs by “normalizing” the result against a standard INR = PT patient/PT Control Antiplatelets Aspirin Inhibits prostaglandin synthesis through irreversible inhibition of cyclooxygenase (COX) Dose: 81-325mg PO daily Typically hold 2-3 days before surgery/procedure Adverse effects: dyspepsia, bleeding, asthma exacerbation, rare rash, hepatotoxicity, thrombocytopenia Monitoring: CBC, platelets, SCr Avoid in children (age 50% platelet fall or nadir >50% platelet fall BUT surgery within /= 20,000 AND no surgery preceding 3 days OR in preceding 3 days OR nadir day 10 or unclear timing