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Block 7 Week 4 Colt > Anticoagulants - LeBlanc > Flashcards

Anticoagulants - LeBlanc Flashcards

1
Q

Desmopressin Acetate is a (anti/pro) coagulant

A

procoagulant

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2
Q

Aspirin, Plavix, and ReoPro are (anticoag/antiPLT)

A

antiPLT

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3
Q

Factor IIa and Xa inhibitors, coumadin, LMWH and unfrac’d heparin are (blank)

A

anticoags

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4
Q

What is streptokinase?

A

A thrombolytic agent like tPA

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5
Q

Protamine sulfate and aminocaproic acid can be given in the event of an overdose of what drug?

A

tPA

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6
Q

For what three reasons does little to know intravascular coagulation occur?

A
  1. dilution of factors
  2. presence of plasma inhibitors
  3. activated clotting factors are removed quickly by the liver
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7
Q

TXA2 and Serotonin released from the PLTs have what effect of vascular tone?

A

causes powerful vasoconstriction of vascular smooth muscle

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8
Q

The (blank) pathway occurs from trauma to the blood itself from large glycoprotein complexes released from PLTs

A

intrinsic pathway

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9
Q

The (blank) pathway occurs from extravascular trauma forming a macromolecular complex with tT

A

extrinsic pathway

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10
Q

What drug prevents the conversion of plasminogen to plasmin?

A

Aminocaproic acid

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11
Q

What two drugs are able to convert plasminogen to plasmin without going through an activation step?

A

tPA and urokinase

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12
Q

Streptokinase bound to its proactivator forms (blank), which can convert plasminogen to plasmn

A

anistreplase

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13
Q

Plasmin favors the degradation of what two molecules?

A

Fibrinogen and fibrin

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14
Q

What are the three direct acting anticoagulants?

A

CHF:
Calcium chelators
Heparin
Factor IIa and Xa inhibitors

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15
Q

What are calcium chelators used for?

A

in vitro testing ( aka sodium citrate and EDTA)

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16
Q

What is the commonly used indirect anticoagulant?

A

Warfarin

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17
Q

What is the most commonly used antiPLT drug?

A

aspirin

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18
Q

(blank) is used to activated the intrinsic pathway

A

kaolin

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19
Q

T/F: heparin is only active in vivo

A

false; active in vivo and vitro

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20
Q

what is the source of commercial heparin?

A

bovine lung or porcine intestinal mucosa

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21
Q

Describe the MOA of heparin?

A
  1. forms complex with a2-globulin AT-III and each of the activated proteases of the cascade (kallikrein, XIIa, XIa, Xa, and thrombin)
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22
Q

T/F: heparin binds irreversibly to its targets

A

false; is released and rebinds to free AT-III

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23
Q

HMWH blocks the conversion of (blank to blank)

A

prothrombin to thrombin

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24
Q

Because HMWH blocks the synth of thrombin, fibrinogen cannot be converted to (blank)

A

fibrin

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25
Q

What two factors is heparin very good at inhibiting?

A

Xa and IIa (thrombin)

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26
Q

T/F: HMWH can also suppress the activity of factors IXa and VIIIa

A

false; IXa and XIa

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27
Q

At low doses, HMWH primarily neutralizes factor (balnk)

A

Xa

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28
Q

At high doses, HMWH prevents (blank)-induced activation of PLTs, and actvation of factors V and VIII

A

thrombin-induced PLT activation

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29
Q

HIT causes bleeding or clotting?

A

clotting, heparin should make you bleed but this shit fucks you up so badly it gets reversed

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30
Q

T/F: heparin may be given orally

A

false

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31
Q

What is the main route of admin for heparin?

A

IV

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32
Q

How long does it take a subQ injection heparin to reach therapeutic levels?

A

2-4 hours

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33
Q

T/F: IM is a viable route to give heparin, it just takes longer

A

false; forms hematomas–makes sense

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34
Q

T/F: heparin may cross the placenta and is present in breast milk

A

false

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35
Q

What are the half lives in hours of 100, 400, and 800 units of heparin?

A

1, 2.5, and 5 hours

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36
Q

What are the contraindications for heparin use?

A 
When bleeding must be avoided:
1. uclerative lesions (GI, cancers)
2. intracranial hemorrhage
3. brain /spinal cord injury
4. pts with thrombocytopenia or history of HIT
5. severe HTN
6 old pts, especially women
7. severe allergies
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37
Q

What drug can you give if you OD your pt on heparin (OOPS!)

A

protamine sulfate at 1mg of PS per 100 units heparin, not to exceed 50mg in 10 minutes

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38
Q

What is the range that you want the aPTT to be in on heparin thearpy?

A

1.5 to 2.5x normal

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39
Q

When should you begin checking factor Xa activity after beginning heparin?

A

6 hour intervals after initiation of heparin infusion

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40
Q

What two values should you pay attention to on the CBC when giving heparin?

A

PLT count and Hct

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41
Q

HMWH will accelerate the interaction of AT-III with both thrombin and factor Xa while LMHW will only accelerate the interaction with (blank)

A

factor Xa

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42
Q

What is the ratio of anti-Xa: anti-IIa in HMHW treatment?

A

1:1

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43
Q

What is the ratio of anti-Xa:anti-IIa in LMHW treatment?

A

4:1

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44
Q

T/F: HMHW and LMWH are equally effective

A

TRUE

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45
Q

The half life of LMWH is how many times longer than HMHW?

A

2x

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46
Q

What is the bioavailability of LMWH for subQ injection? Of UFH?

A

LMWH: 90%

while UFH is only 20%

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47
Q

T/F: lmwh has less frequent bleeding compared to HMHW

A

true

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48
Q

T/F: a fib is an indication for heparin

A

true

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49
Q

T/F: blood transfusions is an indication for heparin

A

true

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50
Q

What are the indications for UFH or LMWH use?

A 
Blood transfusions
Atrial fibrillation
Disseminated intravascular coagulation (DIC)
Open heart surgery
Pulmonary embolism
Venous thromboembolism
Venous catheter occlusion
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51
Q

Are thrombin inhibitors direct or indirect anticoagulants?

A

direct

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52
Q

Which thrombin inhibitor is similar in structure to l-arginine?

A

Argatroban

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53
Q

What thrombin inhibitor was isolated from leech saliva?

A

Hirudin

54
Q

What is the route of admin for thrombin inhibitors?

A

IV infusion

55
Q

When do you use thrombin inhibitors instead of heparin?

A

if the pt is high risk for HIT or if they had a coronary angioplasty or coronary bypass surgery

56
Q

What is the only orally active thrombin inhibitor?

A

Dabigatran

57
Q

What are the indications for using dabigatran?

A

thromboembolic disorders

prophylactic anticoag to minimize stroke risk in pts with NON-VALVULAR a-fib

58
Q

What is the route of admin of factor Xa anticoags?

A

oral

59
Q

What type of drug do you give for DVTs, PE, cerebrovascular accident, or prophylactic or hip or knee replacement?

A

factor Xa inhibitor Xarelto

60
Q

What do you give for cerebral accidents or non-valvular a-fib (new drug)?

A

Eliquis

61
Q

What is the most common oral anticoag?

A

warfarin

62
Q

How long does it take warfarin to become active in vivo?

A

12-24 hours

63
Q

what is the MOA of warfarin?

A

blocks vit. K activation of coag factors; specifically blocks the gamma carboxylation of glutamic acid residues

64
Q

What is the effect of warfarin on protein C?

A

downregulates it

65
Q

When protein C is bound to (blank) on the endothelial cells, it alters the specificity thrombin

A

thrombomodulin

66
Q

Binding of protein C to the endothelial surface favors the degradation of what two factors>?

A

Va and VIIIa

67
Q

T/F: warfarin has procoagulant activity early in therapy

A

true

68
Q

Why does warfarin show procoagulant effects early in treatment

A

because it downregulates anticoag protein C!

69
Q

What factor has the shortest half life?

A

VII; 6 hours

70
Q

What factor has the longest half lives?

A

prothrombin: 60 hours

71
Q

Which factor has a half life of 24 hours?

A

IX

72
Q

WHich factor has a half life of 40 hours?

A

X; 40 is a multiple of 10

73
Q

Warfarin is bound to what plasma protein?

A

albumin

74
Q

How is warfarin metabolized?

A

CYP450 in the liver

75
Q

How is warfarin excereted?

A

by the kidney via urine after liver processing

76
Q

The INR and (PT/PTT) is used to test the coag properties of warfarin

A

PT

77
Q

How do you correct for a warfarin overdose?

A

give Vit. K after 24 hours

transfuse whole blood or plasma for major bleeding

78
Q

What are the contraindications for warfarin?

A

Vit. K deficiency
Hepatic or renal disease
SALICYLATE THERAPY
pregnancy

79
Q

T/F: coumadin can pass the placental barrier

A

TRUE

80
Q

What is the complication of giving coumadin to pregnant moms?

A

abortion or birth defects

81
Q

Why are infants more sensitive to anticoagulants?

A

lower levels of vit. K production due to a lack of gut bacteria to make it

82
Q

What drugs reduce the efficacy of warfarin?

A

cholestyramine
thoset that induce:
hepatic microsomal enzymes (how its cleared)
stimulation of synth of clotting factors (counteracts it)

83
Q

What drugs increase the response to warfarin?

A 
those that:
displace the anticoag from the plasma proteins
inhibit hepatic microsomal enzymes
reduce availability of Vit. K
inhibit synth of clotting factors
decrease PLT aggregation, aka ASPIRIN!!!
84
Q

desmopressin acetate is an analog of what natural hormone?

A

ADH

85
Q

Desmopressin stimulates activity of what factor?

A

vIII

86
Q

WHat do you use desmopressin to treat?

A

hemophilia A with VIII levels greater than 5%, or with VIII Abs

87
Q

What is used to treat von Willebrands’ type 1?

A

desmopressin

88
Q

What is the MOA of Aspirin?

A

inhibits release of ADP by platelets

inhibits PLT aggregation by acetylating COX which prevents tXA2 production

89
Q

Low dose aspiriin (160-320mg) is more effective at inhibiting (TXA2/PGI2)

A

TXA2

90
Q

PGI2 is synthesized by the endothelium and has effects opposite to (blank)

A

TXA2

91
Q

The effect of aspirin is (reversible/irreversible)

A

irreversible

92
Q

T/F: benefit of aspirin to prevent MI is uncertain

A

true

93
Q

T/F: benefit of MI in pts with previous vascular accident is uncertain

A

false; it does help

94
Q

What drug do you use in patients that are at risk of stroke but are intolerant to aspirin?

A

Ticlopidine

95
Q

What is the MOA of ticlopidine?

A

inhibits response to ADP; prevents aggregation via imapairing the GpIIb/IIIa receptor

96
Q

What is the mechanism of Plavix?

A

inhibits response to ADP and aggregation via the GpIIb/IIa pathway like ticlopidine

97
Q

ReoPro is a mAB (blank) fragment of PLT glycoprotein IIb/IIIa

A

Fab

98
Q

What is the MOA of ReoPro?

A

prevents binding of fibrinogen and vWF, which prevents PLT aggregation

99
Q

What are in the indications for ReoPro?

A

acute coronary syndromes and percutaneous coronary intervention

100
Q

Plasminogen is converted to plasmin by the cleavage of how many peptide bonds?

A

one

101
Q

Plasmin is a (specific/nonspecific) protease

A

non-specific

102
Q

What is the major scary SE of thrombolytic agents?

A

hemorrhage at the site of injury

103
Q

why can thrombolytics cause hemorrhage?

A

they dissolve both the pathological clots and the clot at the actual site of injury

104
Q

(blank) is indicated in pts with extensive pulmonary emboli, sever iliofemoral thrmobophlebitis and acute coronary occlusion

A

thrombolytic therapy

105
Q

Stasis from vascular occlusion signals for the release of (blank)

A

tPA

106
Q

tPa binds to (blank) and converts plasminogen

A

fibrin

107
Q

Free plasmin is rapidly inhibited by (blank)

A

a2-antiplasmin

108
Q

T/F: fibrin-bound plasmin is resistant to degradation by a2-antiplasmin

A

true

109
Q

T/F: tPA works to convert plasminogen in the abscence of fibrin

A

false; works very poorly

110
Q

Does tPA prefer fibrin bound plasminogen or serum plasminogen?

A

fibrin bound

111
Q

(blank) is produced by b-hemolytic streptococci and forms a stable 1:1 complex with plasminogen

A

streptokinase

112
Q

what is the enzymatic activity of streptokinase?

A

none! it doesn’t have intrinsic activity, it has to be bound to plasminogen

113
Q

How does binding of streptokinase to plasminogen allow conversion to plasmin?

A

binding changes the confomration that allows for a peptide bond to be cleaved

114
Q

A pt. with a liver biopsy one week prior who had a puncture of the vena cava (non compressible) after a car accident and needed to be shocked (may/may not) receive thrombolytic therapy for DIC

A

may not

115
Q

A pt. with a gastric ulcer of two months becomes septic after systemic infection with H. pylori and develops DIC that leads to a ishcemic stroke. Is tPA indicated?

A

nope; gastric bleeding

116
Q

A patient with chronic hypertension of 130/90 begins coumadin therapy. However, he nonetheless develops a DVT. can tPA be used?

A

no, HTN above 110

117
Q

A patient with a previous stroke (is/isnot) able to get tPA to clear the stroke

A

is not

118
Q

What drug can you give to reverse the states associated with fibrinolysis?

A

aminocaproic acid

119
Q

What are the signs and symptoms of DVT

A
  1. unilateral leg swelling with local tenderness and pain
  2. denies SOB; indicates that the DVT has not progressed to PE
  3. cyanoiss from venous obstruction or reddish color from perivascular inflammation
120
Q

WHat are risk factors associated with forming a DVT?

A
  1. immobilization
  2. coronary artery disease
  3. obesity
121
Q

How do you Dx a DVT?

A
  1. Doppler (aka duplex) ultrasound
  2. fibrinogen scanning (non invasive, detects areas of accumulation)
  3. d-Dimer; tests for fibrin degradation products
  4. Impedence plethysmography (pneumatic cuffs to detect blood volume changes)
122
Q

What anticoagulant should be used in the IMMEDIATE treatment of a DVT?

A

NOT WARFARIN, TOO SLOW
Use heparin IV or subQ LMHW
Elevate the leg and apply heat to help restore blood flow

123
Q

What is the standard dosing regimen of heparin?

A

5000 U IV for loading dose followed by 1,000 U/hr IV for maintanence dose

124
Q

Why do we give such a large loading dose of heparin?

A
  1. helps reach therapeutic concentration faster

2. there is an initial resistance to anti coag drugs because the clotting cascade is in full swing

125
Q

What is the loading dose range of heparin based on body weight?

A

70-100 U/kg

126
Q

What is the maintenance dose range of heparin based on body weight?

A

15-25 U/kg/hr

127
Q

What is the soonest after giving a loading heparin dose that you should measure the aPTT?

A

no sooner than 6 hours

128
Q

If heparin dosing is stable, what three labs should you check once daily?

A
  1. aPTT
  2. Hct
  3. PLT level
129
Q

How long should heparin be maintained for acute onset DVT?

A

7-10 days

130
Q

On what day of hepaarin therapy should warfarin be started?

A

day 5

131
Q

How long should a patient be kept on warfarin after having a DVT?

A

3-6 months

Block 7 Week 4 Colt (9 decks)

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