Coagulations

Questions and Answers

What is the target of Vorapaxar in its anti-platelet action?

PAR-1 receptor (correct)

GPIIb/IIIa receptor

P2Y receptor

Thrombin receptor

Which of the following medications is a fibrinolytic medication used to treat acute thrombotic events such as deep vein thrombosis?

Aspirin

Clopidogrel

Ticagrelor

Streptokinase (correct)

What is the primary mechanism of action of Dipyradimole in its anti-platelet action?

Inhibition of phosphodiesterase (correct)

Inhibition of COX1 enzyme

Antagonism of TXA2 receptors

Blockade of P2Y receptors

Which of the following is NOT an anti-platelet medication?

Tranexamic acid Signup and view all the answers

What is the end result of the fibrinolytic pathway?

Dissolution of fibrin clot Signup and view all the answers

Which of the following anti-platelet medications targets the GPIIb/IIIa receptor?

All of the above Signup and view all the answers

Which of the following is a recombinant tPA used to treat acute ischemic stroke?

Alteplase Signup and view all the answers

What is the relationship between coagulation and fibrinolysis?

Coagulation and fibrinolysis are competing pathways Signup and view all the answers

Which of the following medications is a direct inhibitor of Factor Xa, commonly used for atrial fibrillation, DVT, and pulmonary embolism?

Rivaroxaban Signup and view all the answers

Which of the following is a major concern associated with warfarin use?

Low therapeutic index requiring close monitoring Signup and view all the answers

What is the mechanism of action of heparin, a commonly used anticoagulant?

Activation of antithrombin III Signup and view all the answers

Which of the following is NOT a characteristic of fondaparinux, a type of heparin?

Available in oral form for long-term use Signup and view all the answers

Which of the following is an antidote for dabigatran, a direct thrombin inhibitor?

Idarucizumab Signup and view all the answers

Which of the following medications is NOT considered an anticoagulant?

Aspirin Signup and view all the answers

Which of these antithrombotic drugs inhibits the amplification of thrombus formation by restricting platelet activation?

Aspirin Signup and view all the answers

What is the key role of thrombin in the coagulation cascade?

Conversion of fibrinogen to fibrin Signup and view all the answers

Which of the following conditions is NOT a major cause of thrombosis?

Hypoglycemia Signup and view all the answers

Which of the following statements is TRUE regarding the extrinsic pathway of coagulation?

It is initiated by tissue damage or contact with foreign surfaces. Signup and view all the answers

Which of the following drugs would be MOST effective in dissolving an existing blood clot?

Alteplase Signup and view all the answers

What is the physiological role of glycoprotein IIb/IIIa receptors on platelets?

Binding to collagen and fibrinogen Signup and view all the answers

What is the main mechanism of action of anti-platelet drugs?

Blocking the activation of platelets Signup and view all the answers

A patient with a history of atrial fibrillation is prescribed warfarin for stroke prevention. What is the target INR range for this patient?

2 - 3 Signup and view all the answers

What is the main difference between venous thrombi and arterial thrombi?

Venous thrombi are high in fibrin, while arterial thrombi are high in platelets Signup and view all the answers

Which of the following is a potential complication of using antithrombotic drugs?

Increased risk of bleeding Signup and view all the answers

Study Notes

Thrombosis

Venous thrombi are characterized by high fibrin content, while arterial thrombi are high in platelets
Major causes of thrombosis include:
- Myocardial infarction
- Atherosclerosis
- Vasculitis
- Hypertension
- Smoking
- Radiation
- Chemical irritation
- Inflammation
- Hypoxia
- Infection

Coagulation Pathway

Intrinsic pathway involves factors XII, XI, and IX
Extrinsic pathway involves tissue damage or contact with external bodies, leading to the conversion of prothrombin to thrombin (factor IIa)
Antithrombin III regulates the coagulation process

Fibrin Formation

Thrombin cleaves fibrinogen to form insoluble fibrin
Fibrin strands assemble into fibrils that bind to platelets and each other

Platelet Aggregation

Activated platelets express glycoprotein IIb/IIIa receptors, which bind to fibrinogen and collagen
Release of thromboxane A2 (TXA2) and adenosine diphosphate (ADP) promotes platelet activation

Antithrombosis Drugs and Strategies

Anticoagulants inhibit initiation of thrombin formation
Anti-platelet drugs inhibit platelet activation
Fibrinolytics promote degradation of fibrin strands

International Normalised Ratio (INR)

Prothrombin time measures blood clotting time (normal range: 12-13 seconds)
INR compares prothrombin time to a standardized norm
Therapeutic INR ranges:
- Normal healthy: 0.8-1.2
- Therapeutic: 2-3 or 2.5-3.5
- Dose reduction: 5-9
- Emergency: >8

Anticoagulants - Warfarin

Warfarin is a vitamin K antagonist, the most commonly used anticoagulant in the UK
Mechanism: inhibition of vitamin K-dependent clotting factors

Anti-Platelet Drugs

Examples:
- Clopidogrel
- Prasugrel
- Ticagrelor
- Aspirin
Mechanisms:
- Inhibition of ADP receptors
- Inhibition of thromboxane A2 synthesis
- Inhibition of glycoprotein IIb/IIIa receptors

Fibrinolytics (Thrombolytics)

Examples:
- tPA ( alteplase)
- Streptokinase
- Tranexamic acid
Mechanism: degradation of fibrin strands
Indications:
- Acute thrombotic or embolic events
- Deep vein thrombosis
- Post-myocardial infarction

Fibrinolytics

Streptokinase is a bacterial plasminogen-activating enzyme
Recombinant tPA (alteplase) is used for acute thrombotic or embolic events
Tranexamic acid is used to inhibit fibrinolysis

Anticoagulants - Warfarin Alternatives

Direct inhibitors of factor Xa (e.g. rivaroxaban, apixaban)
Direct thrombin inhibitors (e.g. dabigatran)
IV anticoagulants:
- Heparins (e.g. fondaparinux)
- Hirudins (e.g. lepirudin)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the major causes of thrombosis, including atherosclerosis, hypertension, and smoking, as well as the differences between venous and arterial thrombi.