CVS - Drugs Affecting Platelets and Coagulation Flashcards
What are the stages of haemostasis?
Vasoconstriction, platelet adhesion, activation, aggregation, and fibrin formation.
What are the classifications of anticlotting drugs?
Antiplatelet drugs, anticoagulants, and thrombolytics.
What is the mechanism of action of NSAIDs like Aspirin as antiplatelet drugs?
Inhibition of cyclooxygenase, reducing thromboxane A2 and inhibiting platelet aggregation.
How do GP IIB/IIIA receptor blockers function?
They prevent fibrinogen binding, inhibiting platelet aggregation.
What are examples of ADP receptor blockers?
Ticlopidine and Clopidogrel.
What is the action of PDE inhibitors like Dipyridamole in antiplatelet therapy?
They inhibit platelet aggregation by increasing cAMP levels.
What are the clinical uses of Aspirin as an antiplatelet agent?
Prevention of myocardial infarction, stroke, and other thromboembolic disorders.
What are common adverse effects of Aspirin?
Gastrointestinal bleeding, tinnitus, and Reye’s syndrome.
How does Abciximab function as a GP IIB/IIIA receptor blocker?
It is a monoclonal antibody that binds to the GP IIB/IIIA receptor.
What is the pharmacokinetic profile of Heparin?
Rapid onset of action, administered intravenously or subcutaneously.
What is the mechanism of action of Warfarin?
Inhibition of vitamin K-dependent clotting factors (II, VII, IX, X).
How does Lepirudin work as an anticoagulant?
It directly inhibits thrombin.
What is the function of Antithrombin III in anticoagulation?
It enhances the inactivation of thrombin and other coagulation enzymes.
What is the therapeutic use of tissue plasminogen activator (t-PA)?
To dissolve blood clots in conditions like myocardial infarction and stroke.
How does Urokinase function as a thrombolytic agent?
It directly converts plasminogen to plasmin, leading to clot breakdown.
What is the role of streptokinase in thrombolysis?
It forms a complex with plasminogen, converting it to plasmin.
What are the adverse effects of thrombolytic agents?
Hemorrhage, including intracranial bleeding.
What is the action of Ticlopidine and Clopidogrel?
They irreversibly block ADP receptors on platelets, inhibiting activation.
How is Eptifibatide used in antiplatelet therapy?
As a short-term intravenous agent during percutaneous coronary interventions.
What is the risk associated with GP IIB/IIIA receptor blockers?
They may cause thrombocytopenia and bleeding complications.
What is the indication for using Dipyridamole?
Often used in combination with other agents like aspirin to prevent stroke.
How is Aspirin metabolized?
Rapidly absorbed and metabolized in the liver to salicylic acid.
What is the impact of NSAIDs on renal function?
They can impair renal function and increase blood pressure.
What monitoring is required for patients on Warfarin?
Regular INR monitoring to adjust dosing and avoid bleeding.
What is the advantage of low molecular weight heparins (LMWHs) over standard heparin?
They have a more predictable anticoagulant response and lower risk of bleeding.
How does Hirudin differ from other anticoagulants?
It is a direct thrombin inhibitor derived from leech saliva.
What are the indications for using thrombolytic agents?
Acute myocardial infarction, ischemic stroke, and pulmonary embolism.
How is thrombolytic therapy administered?
Typically intravenously, sometimes directly into the clot during procedures.
What are the contraindications for thrombolytic therapy?
Recent surgery, bleeding disorders, and severe uncontrolled hypertension.
Why is Aspirin used in low doses for antiplatelet therapy?
To minimize side effects while effectively inhibiting platelet aggregation.
What are the risks of combining NSAIDs with anticoagulants?
Increased risk of bleeding and gastrointestinal ulcers.
How do Tirofiban and Eptifibati0de differ from Abciximab?
They are small molecules and non-antibodies, with a shorter half-life.
What is the benefit of ADP receptor blockers in IHD patients?
Reduction in the risk of atherothrombotic events in patients with IHD.
What are the indications for Antithrombin III administration?
Used in hereditary antithrombin deficiency and in certain cases of heparin resistance.
What is the mechanism of action of t-PA in thrombolysis?
It binds to fibrin in a thrombus and converts plasminogen to plasmin.
What are the side effects of using Heparin?
Bleeding, heparin-induced thrombocytopenia, and osteoporosis with long-term use.
What is the role of vitamin K in Warfarin therapy?
Vitamin K is necessary for the synthesis of clotting factors inhibited by Warfarin.
How is Lepirudin dosed in anticoagulation?
It requires dose adjustments in renal impairment.
What is the main use of Urokinase in clinical practice?
Primarily used in pulmonary embolism and severe deep vein thrombosis.
Why is Clopidogrel preferred over Ticlopidine?
Due to a better safety profile and less severe side effects.
What are the monitoring parameters for antiplatelet therapy?
Platelet counts, bleeding times, and signs of bleeding or bruising.
What is the mechanism of action of Dipyridamole in combination with aspirin?
It enhances the antiplatelet effect of aspirin.
What are the main indications for using Beta-blockers
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Why are lipid-lowering drugs important in IHD management?
They help reduce atherosclerotic plaque progression and risk of myocardial infarction.
What is the importance of lifestyle modifications in IHD?
They complement drug therapy in reducing the risk and progression of IHD.
How do oral antiplatelet agents prevent thrombus formation?
They target the adhesion, activation, or aggregation of platelets.
What is the mechanism of action of aspirin as an antiplatelet agent?
Aspirin inhibits cyclooxygenase-1 (COX-1) to prevent platelet aggregation.
What is the onset and duration of clopidogrel’s antiplatelet action?
Antiplatelet action within 2 hours, with a slow offset duration of 7-10 days.
What is the mechanism of action of ticagrelor?
It inhibits P2Y12 through a unique mechanism allowing for quicker offset of action.
What are the thrombin receptor antagonists used in antiplatelet therapy?
Vorapaxar and atopaxar.
How do vitamin K antagonists like warfarin function?
They disrupt the formation of vitamin K-dependent clotting factors.
What are Nonvitamin K oral anticoagulants (NOACs) and their excretion route?
NOACs include dabigatran and factor Xa inhibitors, partially excreted through the kidneys.
How are NOACs used in venous thromboembolism treatment?
Initial therapy with parenteral heparin or higher-intensity NOACs, followed by usual or lower doses for extended prevention.
What is the risk comparison of NOACs to warfarin regarding bleeding?
NOACs have reduced intracranial hemorrhage risk but increased gastrointestinal bleeding risk compared to warfarin.
Is routine monitoring advised for NOAC agents?
No, but qualitative assessment can be made using prothrombin time or activated partial thromboplastin time if necessary.
