Week 5: Anticoagulants Flashcards

1
Q

Which is the following is the preferred medication to reverse the anticoagulant effects of unfractionated heparin?

a) Vitamin K
b) Protamine Sulfate
c) Platelet transfusion
d) Plasma components

A

b- protamine sulfate

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2
Q

The onset of anticoagulation effect of warfarin usually occurs how soon after the initiation of therapy?

a) immediately
b) 1 to 2 days
c) 3 to 5 days
d) 5 to 7 days

A

c - 3 to 5 days

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3
Q

Compared with unfractionated heparin, characteristics of low-molecular-weight heparin (LMWH) include all of the following except:

a) more antiplatelet effect
b) decreased need for monitor of anticoagulant effect
c) longer half-life
d) superior bioavailability

A

a - more antiplatelet effect

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4
Q

What is the international normalized ratio (INR) range recommended during warfarin therapy as part of the management of a patient with DVT?

a) 1.5 to 2.0
b) 2.0 to 3.0
c) 2.5 to 3.5
d) 3.0 to 4.0

A

b - 2.0 to 3.0

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5
Q

Which of the following belongs in the direct thrombin inhibitor class?

a) rivaroxaban
b) dabigatran
c) apixaban
d) edoxaban

A

b - dabigatran

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6
Q

Clotting Cascade

A
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7
Q

Warfarin MOA and unique indication that it must be given for

A
  • Vitamin K antagonist - depletes functional Vitamin K reserves by competitively inhibiting VKORC1 complex, which reduces the ability of the liver to synthesize (produce) the Vitamin K dependent clotting factors (X, IX, VII, and II) - [2+7= 9 which is one less than 10]
  • mechanical heart valve - Warfarin is the only drug FDA approved for this - need INR to be 2.5 to 3.5 (need this INR level if pt has had a previous clot while taking Warfarin)
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8
Q

What enzymes are involved in the metabolism of Warfarin? protein bound?

A
  • CYP2C9 and CYP 1A2
  • LOTS of drug interactions
  • 99% protein bound so small changes can lead to changes in blood level of warfarin
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9
Q

Warfarin precautions/ contraindications

A
  • severe HTN
  • NO in infective endocarditis
  • Preg category X
  • caution in hepatic impairment (reduces hepatic synthesis of clotting factors)
  • hypermetabolic state (avoid)
  • safest in patients with kidney disease because of frequent monitoring
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10
Q

The effects of Warfarin may be decreased by:

a) Carbamazepine
b) Vitamin K rich foods
c) Oral contraceptives
d) all of the above

A

D -all of the above

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11
Q

What can you give if the patient taking warfarin has an seriously elevated INR?

A

give Vitamin K

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12
Q

Warfarin ADRs

A
  • thrombocytopenia
  • hemorrhagic skin necrosis & cyanotic toes
  • maculopapular rash eruption
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13
Q

Situations when the NP should consider decreasing the initial dose of Warfarin therapy:

A
  • pt is older than 75 years old
  • multiple comorbid conditions
  • elevated liver enzymes
  • changing thyroid status
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14
Q

Heparin MOA & indication

A
  • DVT/PE; prophylaxis
  • increases the action of antithrombin III (a naturally occurring antithrombotic agent) thereby inactivating thrombin and inhibiting the activity of numerous coagulating factors
  • prevents the conversion of fibrinogen to fibrin
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15
Q

Heparin cautions/contraindications

A
  • use caution when combining w/ conditions/drugs that may predispose to hyperkalemia
  • NO pregnancy
  • ok with lacation
  • NO in advanced renal or hepatic impairment
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16
Q

Heparin ADRs

A
  • hyperkalemia
  • thrombocytopenia
  • anemia
17
Q

Low Molecular Weight Heparin (LMWH) MOA & indication

drug of choice for?

A
  • potentiates the activity of antithrombin III and inactivates factors Xa and IIa (prothrombin)
  • DVT/PE, prophylaxis
  • great for pregnant women!
18
Q

LMWH cautions/contraindications

A
  • avoid allergies with pork, sulfites, or benzyl alcohol
  • use cautiously in renal impairment, untreated HTN, retinopathy, and severe liver dz.
19
Q

Dabigatran (Pradaxa) MOA & indication

A
  • Direct thrombin inhibitor (DTI)
  • thrombin is required to turn fibrinogen into fibrin
  • prodrug
  • indication: reduce risk stroke and embolism in afib
20
Q

dabigatran (Pradaxa) ADRs

A
  • dyspepsia (indigestion)
  • gastritis
  • hemorrhage
21
Q

Dibigatran (Pradaxa) caution/ contraindications

antidote

A
  • NO pregnancy/lactation
  • black box warning: epidural or spinal hematomas with spinal interventions
  • black box warning: discontinuation and increase of thrombotic events

Antidote: Praxbind (Idarucizumab)

22
Q

Rivaroxaban (Xarelto), Apixaban (Eliquis), Edoxaban (Savaysa), and Betrixaban (Bevyxxa) MOA & indication

A

Xa-ban” drugs - direct factor Xa inhibitors

  • indication: tx DVT and/or PE and reduce stroke & embolism afib
23
Q

Rivaroxaban (Xarelto) ADR

A

back pain, abdominal pain, dyspepsia

24
Q

Apixaban ADRs

A

nausea

25
Q

Edoxaban ADR

A

Skin rash and GI bleeding, vag lbeeding, dermal bleeding

26
Q

Edoxaban antidote

A

andexanet alpha (Andexxa )

27
Q

Rivaroxaban, Apixaban, Edoxaban, and Betrixaban cautions/ contraindications

A
  • black box warning: discontinuation would cause an increase in thrombotic events, epidural or spinal hematomas with spinal interventions

NO pregnancy or lactation

Rivaroxaban: NO in pts mod-severe liver impairment & CC < 30

Apixaban and edoxaban: NO in < 15 creatinine clearance (caution in moderate, NO in severe liver impairment)

28
Q

Anticoagulants vs Antiplatelets

A

Anticoagulants:

  • affect the clotting cascade
  • makes the blood less able to create clots and thinning the blood

Antiplatelets:

  • makes your platelets less sticky and unable to create clots