List: Anticoagulants and Thrombolytic Drugs Flashcards

1
Q

Hemostasis:

A

Hemostasis: process that maintains the integrity of the circulatory systems after vascular damage

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2
Q

Primary hemostasis:

A

Primary hemostasis: platelet plug formation (platelets adhere to damaged endothelium to form plug)

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3
Q

Secondary hemostasis:

A

Secondary hemostasis: blood coagulation (clot forms upon the conversion of fibrinogen to fibrin, and its addition to the platelet plug) –> Formation of a thrombus

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4
Q

Thrombus Formation:

A

Thrombus Formation: extrinsic and intrinsic pathways merge into common pathway, leading to factor X activation

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5
Q

Factor X to fibrin:

A

Factor X cleaves prothrombin –> thrombin

Thrombin cleaves fibronigen –> fibrin

Fibrin incorporated into thrombus

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6
Q

Thrombolysis/Fibronolysis:

In response to injury, endothelial cells synthesize and release:

t-PA converts plasminogen:

Plasmin cleaves:

A

Thrombolysis/Fibronolysis: process of fibrin digestion by plasmin (protease)

  • In response to injury, endothelial cells synthesize and release tissue plasminogen activator (t-PA)
  • t-PA converts plasminogen  plasmin
  • Plasmin cleaves fibrin and dissolves the clot
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7
Q

Endogenous Inhibitors of this Process

PAI-1/PAI-2:
α2-antiplasmin:

A

PAI-1/PAI-2: inhibit t-PA

α2-antiplasmin: inhibitor of plasmin

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8
Q

3 Major Classes of Anticoagulant Drugs:

A

Indirect Thrombin Inhibitors

Parenteral Direct Thrombin Inhibitors

Oral Anticoagulants

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9
Q

Indirect Thrombin Inhibitors:
Parenteral Direct Thrombin Inhibitors:
Oral Anticoagulants:

A

Indirect Thrombin Inhibitors: Heparin, Fodaparinux

Parenteral Direct Thrombin Inhibitors: Hirudin, Bivalirudin, Argatroban

Oral Anticoagulants: Warfarin, next generation drugs (Apixaban, Pradaxa, Rivaroxaban)

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10
Q

Indirect Thrombin Activators

General MOA:

A

General MOA: antithrombotic effect due to interaction with antithrombin III (ATIII) and factor Xa

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11
Q

Indirect Thrombin Activators

Preparations: (3)

A

o Unfractionated heparin
o Low-molecular weight heparin
o Fondaparinux (synthetic polysaccharide)

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12
Q

Heparin

General:

A

General: heterogeneous mixture of sulfated mucopolysaccharides

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13
Q

Heparin Targets: (3)

A
  • Thrombin
  • Factor Xa
  • Factor IXa
    .
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14
Q

Heparin

MOA:

A

MOA: activated ATIII binds heparin and efficiently degrades thrombin and factor X

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15
Q

Heparin

Therapeutic Use: (6)

A
  • Venous thrombosis (initial treatment)
  • Pulmonary embolism (initial treatment)
  • Acute MI (initial treatment)
  • Surgery requiring cardiopulmonary bypass
  • Patients with DIC
  • Unstable angina
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16
Q

Heparin
Pharmacokinetics:
LMW can be given ____ and without ______

A

Pharmacokinetics: LMW heparin preparations have more predictable pharmacokinetics than HMW heparin
- LMW can be given subQ and without laboratory monitoring

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17
Q

Management of Heparin Treatment

Full-dose heparin therapy:
subQ heparin:

A

Full-dose heparin therapy by continuous IV infusion needs to be monitored by activated partial thromboplastin time (aPTT)

Can give subQ heparin for long-term anticoagulant therapy in patients with contraindications for warfarin use (ie. pregnancy)

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18
Q

Heparin
Toxicity

Bleeding:
Protamine Sulfate:
Heparin-induced thrombocytopenia:

A

Bleeding: incidence somewhat less in patients treated with LMW form
- Protamine Sulfate: can be given in cases of life-threatening hemorrhage to reverse the effects of heparin (binds tightly and neutralizes it)

Heparin-induced thrombocytopenia: decreased platelet count; lower incidence with LMW form

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19
Q

Fondaparinux

Use:

A

Use: approved for thromboprophylaxis of patients undergoing hip or knee surgery
- To prevent pulmonary embolism and deep vein thrombosis

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20
Q

Fondaparinux

Management:

A

Management: similar to LMW heparin

  • Can be used with daily subQ administration
  • Does not require monitoring
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21
Q

Parenteral Direct Thrombin Inhibitors

Drugs in this Class: (3)

A

Hirduin
Bivalirudin
Argatroban

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22
Q

Hirduin:
Bivalirudin:
Argatroban:

A

Hirduin: bivalent specific, irreversible thrombin inhibitor (leech saliva)
Bivalirudin: bivalent inhibitor of thrombin
Argatroban: small molecule thrombin inhibitor

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23
Q

Parenteral Direct Thrombin Inhibitors

Drug Targets:

A

Thrombin

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24
Q

Therapeutic Use/Management
Hirudin

Treatment of patients with:
Administered by:
Dose adjusted to maintain:

A
  • Treatment of patients with heparin-induced thrombocytopenia
  • Administered by IV
  • Dose adjusted to maintain aPTT at 1.5-2
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25
Q

Therapeutic Use/Management
Bivalirudin

Alternative to:
Administered by:

A
  • Alternative to heparin in patients undergoing coronary angioplasty
  • Administered by IV
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26
Q

Therapeutic Use/Management
Argatroban

Alternative to:

A

Alternative to hirudin for prophylaxis treatment of patients with or at risk of developing heparin-induced thrombocytopenia

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27
Q

Parenteral Direct Thrombin Inhibitors
Toxicity

Use with caution in renal failure:
Development of anti-hirudin Abs:

A

Use with caution in renal failure: can accumulate and cause bleeding

Development of anti-hirudin Abs: can cause paradoxical increase in aPTT (daily monitoring of aPTT recommended)

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28
Q

Warfarin

General:

A

General: synthetic derivative of coumarin

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29
Q

Warfarin

Administered as:
bioavailability:
T½:
vs heparin:

A
  • Administered as a sodium salt
  • Has 100% bioavailability
  • Long T½ in plasma (36 hours)
  • Slower acting than heparin (for long term management, NOT for an acute event)
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30
Q

Warfarin

MOA:
Blocks ______ of glutamate residues in coagulation factors

A

MOA: inhibits the vitamin-K dependent synthesis of biologically active forms of the Ca++-dependent clotting factors (prothrombin, VII, IX, X) and protein C (regulatory factor)
- Blocks gamma-carboxylation of glutamate residues in coagulation factors

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31
Q

Warfarin
Therapeutic Use

Prevent progression or recurrence of:
Prevention of ____________ in patients undergoing orthopedic or gynecological surgery

A

Prevent progression or recurrence of acute DVTs or pulmonary embolism (follows initial course of heparin)

Prevention of venous thromboembolism in patients undergoing orthopedic or gynecological surgery

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32
Q

Warfarin

Preventing systemic emboli in patients with: (3)

A

Preventing systemic emboli in patients with:

  • Acute MI
  • Prosthetic heart valves
  • Chronic atrial fibrillation
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33
Q

Warfarin
International Normalized Ration (INR)

Therapeutic range for:
Defined as:
Prothrombin time determined from:

A

International Normalized Ration (INR): therapeutic range for oral anticoagulant therapy

Defined as patient prothombin time/mean of normal prothrombin time for the lab

Prothrombin time determined from a fasting blood sample obtained 8-14 hours after the last dose of an oral anticoagulant

34
Q

Warfarin

Use with caution in patients with: (3)

A

Patients with congenital coagulation deficiency

Patients with thrombocytopenia

Patients with hepatic or renal insufficiency

35
Q

Warfarin

Never use:

A

Patients who are pregnant (readily crosses the placenta and causes hemorrhagic disorder in the fetus/serious birth defects)

36
Q

Warfarin resistance:

Difficult to manage because:

A

Warfarin resistance: can develop in some patients (most common in those with advanced cancer); progression/recurrence of the thrombotic event
- Difficult to manage because raising INR in these patients also increases risk of bleeding

37
Q

Warfarin
DDIs

Decrease anticoagulant effect:

A

Decrease anticoagulant effect: barbiturates and rifampin

38
Q

Warfarin
DDIs

Increase anticoagulant effect:

A

Increased anticoagulant effect: aspirin and cephalosporins

39
Q

Oral Direct Thrombin Inhibitors

Main advantage to these new ones is:
New Drugs: (3)

A

New Drugs: main advantage to these new ones is that they do not require drug monitoring
o Pradaxa: targets thrombin only (already FDA approved)
o Rivaroxiban: targets factor Xa
o Apixaban: targets factor Xa

40
Q

Oral Direct Thrombin Inhibitors (apart from warfarin)

Pradaxa:
Rivaroxiban:
Apixaban:

A

Pradaxa: targets thrombin only (already FDA approved)

Rivaroxiban: targets factor Xa

Apixaban: targets factor Xa

41
Q

Fibrinolytic Drugs

General MOA:

A

General MOA: cause rapid lysis of thrombi by catalyzing the activation of plasmin

42
Q

Fibrinolytic Drugs
Tissue Plasminogen Activator (tPA)

General:

A

General: endogenous serine protease that is a poor plasminogen activator in the absence of fibrin

43
Q

Fibrinolytic Drugs
Tissue Plasminogen Activator (tPA)

MOA:
Presence of fibrin _____ the speed of activation
Clearance:
Half Life:

A

MOA: binds to fibrin via lysine binding sites at amino terminus and activates bound plasminogen
- Presence of fibrin increases the speed of activation several hundredfold

Clearance: occurs by hepatic metabolism
- Half Life: 5-10 minutes

44
Q

Fibrinolytic Drugs
Tissue Plasminogen Activator (tPA)
Use: (3)

A

Use: lyses thrombi during the treatment of

  • Acute MI
  • Pulmonary embolism
  • Severe DVT
45
Q

Recombinant tPA: (2)

Effect on half lives:

A

Recombinant tPA: Reteplase and Tenecteplase

Increased half lives (allow for convenient bolus dosing)

46
Q

Fibrinolytic Drugs
Streptokinase

General:

A

General: produced by beta-hemolytic streptococci

47
Q

Fibrinolytic Drugs
Streptokinase

MOA:

A

MOA: no intrinsic enzymatic activity, but forms a stable complex with plasminogen, producing a conformational change that exposes the active site on plasminogen –> plasmin

48
Q

Fibrinolytic Drugs
Streptokinase

Use:

A

Use: decreased due to advent of newer agents

49
Q

Fibrinolytic Drugs

Recent Studies:

A

Recent Studies: suggest that angioplasty without stent placement is superior to thrombolytic therapy, when it is feasible

50
Q

Fibrinolytic Drugs
Hemorrhage:
_____ at sites of vascular injury

A

Hemorrhage: major toxicity of all thrombolytic agents; results from 2 factors

Lysis of fibrin in physiological thrombi at sites of vascular injury

51
Q

Fibrinolytic Drugs
Hemorrhage

A systemic lytic state that results from systemic formation of plasmin, causing: (2)

A
  • Fibrinogenolysis

- Destruction of other coagulation factors (V and VIII especially)

52
Q

Fibrinolytic Drugs
Toxicity

Aminocaproic acid:

A

Aminocaproic acid: potent inhibitor of fibrinolysis (blocks interaction of fibrin and plasmi) and can reverse excessive fibrinolysis

53
Q

Contraindications to Thrombolytic Therapy

Any of the following within 10 days: (4)

A
  • Surgery (including organ biopsy)
  • Puncture of noncompressible vessels
  • Serious trauma
  • Cardiopulmonary resuscitation
54
Q

Contraindications to Thrombolytic Therapy

Within 3 months:
History of :
Active ____ or _____ disorder

A

o Within 3 months: serious GI bleeding
o History of HTN (diastolic >110 mmHg)
o Active bleeding or hemorrhagic disorder

55
Q

Contraindications to Thrombolytic Therapy

CV:
Aorta;
Pericardium:

A

o Previous cerebrovascular accident or active intracranial process
o Aortic dissection
o Acute pericarditis

56
Q

Antiplatelet Drugs: (4)

A
  • Aspirin
  • Dipyridamole
  • Clopidogrel (Plavix)
  • Ticlopidine
57
Q

Aspirin

MOA:
Acetylates ______ near the active site of ______
Effects last for:

A

MOA: blocks platelet aggregation and vasoconstriction by inhibiting synthesis of thromboxane A2

Acetylates a serine residue near the active site of COX-1 (responsible for production of precursor of TXA2)

Effects last for the life of the platelet (7-10 days)

58
Q

Aspirin

Low dose immediately after a heart attack to :
Low dose long-term for prevention of: (3)

A

Low dose immediately after a heart attack to reduce the risk of another or to prevent the death of cardiac tissue

Low dose long-term for prevention of:

  • Heart attacks
  • Strokes
  • Blood clot formation
59
Q

Aspirin
Toxicity

At higher doses:
Use in combination with _______ increases risk of upper GI bleeding

A

Increased at higher doses (especially bleeding)

Use in combination with clopidogrel or warfarin increases risk of upper GI bleeding

60
Q

Dipyridamole

MOA:

A

MOA: vasodilator

61
Q

Dipyridamole

Use:

A

Use: only recommended for postoperative prophylaxis of thromboemboli in patients with prosthetic heart valves, in combination with warfarin

62
Q

Dipyridamole
Toxicity

most common:
most severe:

A

N/V/D most common

Leukopenia is most severe

63
Q

Clopidogrel (Plavix)

MOA:

A

MOA: platelet ADP receptor antagonist (inhibits platelet activation)

64
Q

Clopidogrel (Plavix)

Use: (4)

A

Used with aspiring after angioplasty (continued for at least 1 year)

Reduce stroke and MI in patients with recent strokes and MIs

Treatment of peripheral arterial disease

Treatment of acute coronary syndrome

65
Q

Clopidogrel (Plavix)
Toxicity

Vs dipyridamole and ticlopidine:
Less frequent cases of:

A

Toxicity: more favorable side effect profile that dipyridamole and ticlopidine

Less frequent cases of thrombocytopenia and leukopenia

66
Q

Ticlopidine

MOA:

A

MOA: platelet ADP receptor antagonist (inhibits platelet activation)

67
Q

Ticlopidine

Use:

A

Reduce the risk of thrombotic stroke in patients who have experience stroke precursors and/or in patients who have had a completed thrombotic stroke

68
Q

Ticlopidine
Toxicity

most common:
most severe:

A

N/V/D most common

Leukopenia is most severe

69
Q

Glycoprotein IIb/IIIa Inhibitors

Inhibit platelet aggregation by blocking: (2)

A

Glycoprotein IIb/IIIa Inhibitors: inhibit platelet aggregation by blocking the binding of these platelet-surface integrins to fibrinogen and von Willebrand factor (block cross-linking of platelets)

70
Q

Glycoprotein IIb/IIIa Inhibitors: (3)

A

o Abciximab
o Eptifibatide
o Tirofiban

71
Q

Abciximab

MOA:

A

MOA: Fab fragment of a humanized mAb against the AlphaIIbBeta3 receptor

72
Q

Abciximab
Use

In conjunction with ______ for coronary thromboses

Use along with aspirin and heparin effective in preventing: (3)

A

In conjunction with percutaneous angioplasty for coronary thromboses

Use along with aspirin and heparin effective in preventing restenosis, recurrent MI and death

73
Q

Abciximab

Major side effect:
If severe:

A

Toxicity: major side effect is bleeding

If severe: platelet transfusions can reverse aggregation defect

74
Q

Eptifibatide

MOA:

A

MOA: cyclic peptide inhibitor of the fibrongen binding site on AlphaIIbBeta3 integrin

75
Q

Eptifibatide
Use

Treatment of:
What have reduced MI and death by ~20%?

A

Treatment of acute coronary syndrome (IV)

Angioplastic coronary interventions (IV)- have reduced MI and death by ~20%

76
Q

Eptifibatide

Major side effect:
If severe:

A

Toxicity: major side effect is bleeding

If severe: platelet transfusions can reverse aggregation defect

77
Q

Tirofiban

MOA:

A

MOA: nonpeptide, small-molecule inhibitor of AlphaIIbBeta3 integrin

78
Q

Tirofiban

Use in conjunction with:
For: (2)

A

Use: in conjunction with heparin

  • Non-Q wave MI
  • Unstable angina
79
Q

Tirofiban

Toxicity:
What is possible?
Transfusions required to:

A

Toxicity: bleeding on local sites of clinical intervention and systemically

Major bleeding possible

Transfusions required to terminate bleeding

80
Q

Example of Treatment Regimen for Acute MI

Prehospital: (4)

A

o Aspirin
o Oxygen (CPR if necessary)
o Analgesia/ECG/Antiarryhtmics
o Defibrillation

81
Q

Example of Treatment Regimen for Acute MI

Hospital: (5)

A

o Antiarrhythmics an same supportive care as above
o Fibrinolytic therapy (up to 12 hours after onset), OR
o Coronary angioplasty, OR
o Coronary artery bypass graft surgery
o Anticoagulant (aspirin, heparin, start on warfarin)

82
Q

Example of Treatment Regimen for Acute MI

Outpatient: (3)

A

o Antiarrhythmics as necessary
o Anticoagulant (aspirin or warfarin)
o Antiplatelet drug