CVS - Anti-thrombotic Agents Flashcards Preview

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Flashcards in CVS - Anti-thrombotic Agents Deck (19):
1

Classes of anti-thrombotic drugs & examples

Anti-Platelet Drugs
1. Aspirin (NSAID)
2. Thienopyridine (Ticlopidine, Clopidogrel)
3. GPIIb/IIIa Antagonist (Abciximab, Eptifibatide, Tirofiban)
4. Phosphodiesterase Inhibitors (Dipyridamole, Cilostazol)

Anticoagulants
1. Heparin (HMW, LMW)
2. Warfarin

Fibrinolytics
1. Streptokinase
2. Urokinase
3. Tissue Plasminogen Activator

2

Mechanism of action of aspirin

Inhibits COX-1 permanently (irreversible acetylation)
- Inhibits TXA2 synthesis in platelets + inhibits PGI2 in endothelial cells - affects platelet activation & aggregation

3

Uses of aspirin

1. Prevention of arterial thrombosis eg MI, stroke

4

Toxicity of aspirin (3)

1. Peptic Ulcer
2. GI Bleeding
3. Allergy

5

Mechanism of action of clopidogrel

Inhibits ADP-induced platelet aggregation, platelet is inhibited throughout its lifespan

6

Uses of clopidogrel

1. Prophylaxis to arterial thrombosis, alternative to aspirin

7

Toxicity of clopidogrel (5)

1. Nausea
2. Dyspepsia
3. Diarrhea
4. Skin rash
5. Hemorrhage

Ticlopidine has more - Neutropenia, thrombotic thrombocytopenic purpura

8

Mechanism of action of abciximab

Antagonizes GPIIb/IIIa receptor, prevents binding of fibrinogen - prevents platelet aggregation

9

Uses of abciximab

Angioplasty regime in high risk patients - less ischemic complications & restenosis (aspirin + heparin + abciximab)

10

Toxicity of abciximab (3)

1. Bleeding
2. Thrombocytopenia
3. Human anti-mouse antibody reactions

11

Mechanism of action of heparin

1. Binds & activates anti-thrombin III (plasma protease inhibitor) - enhanced ATIII interaction with clotting factors IIa, VIIa, IXa, XA to form inactive complexes - inhibits action of clotting factors
2. Stimulates tissue factor pathway inhibitor (TFPI) release from endothelium - inhibits extrinsic pathway

12

Uses of heparin (3)

1. Treatment & Prophylaxis of venous thromboembolism (DVT, PE) (HMW, LMW)
2. Arterial thrombosis (MI) (HMW)
3. Pregnant women at risk of thrombosis (HMW)

13

Toxicity of heparin (6)

1. Bleeding (8-10%)
2. Allergy
3. Heparin-induced Thrombocytopenia (Transient 25%, Severe 5%) (less in LMW)
4. Osteoporosis/Spontaneous fractures (long term) (less in LMW)
5. Transient reversible alopecia (long term)
6. Mineralocorticoid deficiency (long term)

14

Mechanism of action of warfarin

1. Inhibits vitamin K epoxide reductase (converts inactivated vit K to active form, which is req in the activation of factors II, VII, IX, X, protein C)
2. Blocks regeneration of activated Vit K - inhibition of synthesis of clotting factors

Action takes longer as it does not inhibit activity of factors that have already been synthesised

15

Uses of warfarin (4)

1. Maintenance of anti coagulant therapy
2. Prophylaxis & treatment of venous thromboembolism (DVT, PE)
3. Patients who suffered MI, stroke, transient ischemic attack
4. Potent rodenticide

16

Toxicity of warfarin + Contraindications (3+1)

1. Bleeding
2. Cutaneous necrosis
3. Infarction of breast, buttock, intestine, extremities

Crosses placenta
1. Pregnancy - Fetal warfarin syndrome - teratogenic - Bone/CNS defects, hemorrhagic fetus, abortion

17

Overdose of anticoagulants

1. Discontinue
2. Antidotes
- Heparin - Protamine sulfate
- Warfarin - Vitamin K (phytonadione)

18

Uses of fibrinolytics (3)

1. AMI
2. Acute ischemic stroke
3. Acute pulmonary embolism

19

Toxicity of fibrinolytics (3)

1. Hemorrhage
2. Allergy (SK)
3. Anti-SK Ab (SK)