Ch 52: Anticoagulant, Antiplatelet, and Thrombolytic Drugs Flashcards Preview

Lehne's Pharmacology for Nursing Care, 9th ed. > Ch 52: Anticoagulant, Antiplatelet, and Thrombolytic Drugs > Flashcards

Flashcards in Ch 52: Anticoagulant, Antiplatelet, and Thrombolytic Drugs Deck (61)
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1
Q

What are the 2 stages of hemostasis?

A

formation of a platelet plug, and reinforcement of the platelet plug with fibrin

(p. 594)

2
Q

The intrinsic clotting pathway is also known as…

A

…the contact activation pathway.

p. 594

3
Q

The extrinsic clotting pathway is also known as…

A

…the tissue factor pathway.

p. 594

4
Q

At what factor do the two pathways converge?

A

Factor Xa

p. 594

5
Q

What is tissue factor?

A

a complex of several compounds, also known as tissue thromboplastin.

(p. 594)

6
Q

Each platelet has ______ to ______ GP IIa/IIIb receptors.

A

50,000 - 80,000

p. 594

7
Q

What does the letter “a” after a factor’s name indicate?

A

active form

p. 596

8
Q

Which clotting factors are vitamin K-dependent for their synthesis?

A

II, VII, IX, and X
(2, 7, 9, 10)

(p. 597)

9
Q

What does antithrombin do?

A

it forms a complex with clotting factors, inhibiting their activity.

(p. 597)

10
Q

What is plasmin?

A

An enzyme that degrades the fibrin meshwork of a clot.

p. 597

11
Q

The fibrinolytic drugs act by…

A

…promoting the conversion of plasminogen into plasmin

p. 597

12
Q

The antiplatelet drugs are most effective at…

A

…preventing arterial thrombosis.

p. 597

13
Q

Anticoagulants are most effective against…

They work by reducing…

A

…venous thrombosis.
…the formation of fibrin.

(p. 597)

14
Q

What is the MOA of heparin?

A

Enhancement of the activity of antithrombin, a protein that inactivates thrombin (factor IIa) and factor Xa; the ultimate effect is suppression of fibrin formation.

(p. 597, 598)

15
Q

What are the pharmacokinetics of heparin?

A

Hepatic metabolism followed by renal excretion.
The half life is about 1.5 hrs.

(p. 599)

16
Q

What does aPTT stand for?

A

activated partial thromboplastin time

p. 599

17
Q

What is the underlying cause of HIT?

A

development of antibodies against heparin-platelet protein complexes.

(p. 601)

18
Q

HIT should be suspected whenever platelet counts…

A

…fall significantly or when thrombosis develops despite adequate anticoagulation.

(p. 601)

19
Q

In heparin-treated patients, platelet aggregation is the major…

A

…remaining defense against hemorrhage.

p. 601

20
Q

What are the 3 advantages of LMW heparins?

A

As effective as unfractionated heparin.
Easier to use because of fixed dosage.
No aPTT monitoring.

(p. 602)

21
Q

What are the pharmokinetic advantages of LMW heparins over unfractionated heparin?

A

LMW heparins have a higher bioavailability (d/t a lack of nonspecific binding) and a longer half-life.

(p. 603)

22
Q

What 2 LMW heparins are available in the U. S.?

A

enoxaparin and daltaparin

p. 603

23
Q

In contrast to overdose with heparin or LMW heparins, fondaparinux…

A

…cannot be treated with protamine sulfate.

p. 604

24
Q

True or false? Fondaparinux can promote immune-mediated HIT.

A

FALSE, it cannot, although it still can lower platelet counts.

(p. 604)

25
Q

What can spinal or epidural hematoma result in?

A

permanent paralysis

p. 604

26
Q

How does heparin differ from LMW heparins and fondaparinux?

A

The LMW heparins and fondaparinux preferentially inactivate factor Xa, not thrombin (factor IIa).

(p. 600)

27
Q

Warfarin works by inhibiting vitamin K epoxide reductase complex 1 (VKORC1), the enzyme needed to…

A

…convert vitamin K to its active form.

p. 604

28
Q

Warfarin is inactivated in the liver, mainly by…

A

…CYP2C9.

p. 604

29
Q

What are the 3 new oral anticoagulants?

A

dabigatran (Pradaxa), apixaban (Eliquis), and rivaroxaban (Xarelto)

(p. 604)

30
Q

The new oral anticoagulants pose a significantly lower…

A

…risk of serious bleeding.

p. 605

31
Q

Warfarin is inactivated in the liver, mainly by…

A

…CYP2C9.

p. 604

32
Q

What are the 3 new oral anticoagulants?

A

dabigatran (Pradaxa), apixaban (Eliquis), and rivaroxaban (Xarelto)

(p. 604)

33
Q

The new oral anticoagulants pose a significantly lower…

A

…risk of serious bleeding.

p. 605

34
Q

Warfarin is in what pregnancy risk category?

A

X

p. 606

35
Q

When the __________ effects of warfarin are coupled with the antiplatelet and ___________ effects of aspirin, the potential for hemorrhage is significant.

A

antifibrin; ulcerogenic

p. 606

36
Q

Even though it has not been proven acetaminophen is believed to _______ warfarin ___________.

A

inhibit; degradation

p. 607

37
Q

Name at least 5 of the many circumstances in which warfarin is contraindicated.

A

(1) severe thrombocytopenia
(2) uncontrolled bleeding
patients undergoing (3) lumbar puncture, (4) regional anesthesia, or surgery of the (5) eye, (6) brain, or (7) spinal cord
(8) vitamin K deficiency
(9) liver disease
(10) alcoholism

(p. 607)

38
Q

Where heparin inhibits only free thrombin, dabigatran (Pradaxa) binds with and inhibits thrombin that is…

A

…free in the blood as well as thrombin that is bound to clots.

(p. 608)

39
Q

In the event of life-threatening hemorrhage in a patient taking dabigatran, treatment should include…

A

…recombinant factor VIIa or factor IX complex.

p. 608

40
Q

What kind of drug is bivalirudin (Angiomax)?

A

an IV direct thrombin inhibitor

p. 610

41
Q

What is the half-life of bivalirudin (Angiomax) in patients with normal renal function?

A

25 minutes

p. 610

42
Q

Bivalirudin is intended to be given in combination with…

A

…aspirin, clopidogrel, or prasugrel to prevent clots during coronary angioplasty.

(p. 610)

43
Q

Desirudin (Iprivask) is what kind of drug?

How is it given?

A

a direct thrombin inhibitor; it is given subQ

p. 610

44
Q

What kind of drug is rivaroxaban (Xarelto)?

A

an oral anticoagulant that causes selective inhibition of factor Xa.

(p. 610)

45
Q

Fondaparinux is closely related in structure and function to…

A

…heparin and the LMW heparins.

p. 603

46
Q

Fondaparinux is a ____ anticoagulant that ________ the activity of ____________, causing selective __________ of factor __.

A

subQ; enhances; antithrombin; inhibition; factor Xa.

p. 603

47
Q

The term nonvalvular atrial fibrillation pertains to patients who do not have a __________ heart valve or _______________ significant valve disease.

A

prosthetic; hemodynamically

p. 611

48
Q

What are the implications of treatment for overdose with a drug that is highly protein bound?

A

Dialysis is unlikely to remove it from the blood.

p. 611

49
Q

What type of drug is apixaban (Eliquis)?

A

an oral anticoagulant that causes selective inhibition of factor Xa.

(p. 612)

50
Q

What is antithrombin?

A

An endogenous compound that suppresses coagulation by inhibiting thrombin and factor Xa.

(p. 612)

51
Q

Recombinant antithrombin (rhAT) sold as ATryn, is produced in…

A

…the milk of goats that have been given the DNA sequence for human AT.

(p. 612)

52
Q

What are the 3 major groups of antiplatelet drugs?

A

aspirin, P2Y 12 ADP receptor antagonists, and GP IIb/IIIa receptor antagonists

(p. 613)

53
Q

Aspirin and the P2Y 12 ADP receptor antagonists affect only one pathway in platelet aggregation, hence…

A

…their antiplatelet effects are limited.

p. 613

54
Q

Aspirin suppresses platelet aggregation by…

A

…causing irreversible inhibition of cyclooxygenase, an enzyme required by platelets to synthesize TXA2 (thomboxane A2).

(p. 613)

55
Q

Since inhibition of cyclooxygenase by aspirin is irreversible, and since platelets lack the machinery to synthesize new cyclooxygenase, the effects of a single dose of aspirin persist for…

A

…the life of the platelet (7-10 days).

p. 613

56
Q

Which 3 of the 4 P2Y12 ADP receptor antagonists cause irreversible receptor blockade?

A

clopidogrel (Plavix), prasugrel (Effient), and ticlopidine

p. 614

57
Q

Which of the 4 P2Y12 ADP receptor antagonists cause reversible receptor blockade?

A

ticagrelor (Brilinta)

p. 614

58
Q

It patients with ACS, clopidogrel should…

A

…always be combined with aspirin.

p. 614

59
Q

What is one important aspect of treatment in patients who develop TTP from taking clopidogrel?

A

plasmapheresis

p. 614

60
Q

PPIs may reduce the antiplatelet effects of ___________ because they inhibit CYP___.

A

clopidogrel; 2C19

p. 614

61
Q

The GP IIb/IIIa receptor blockers include what 3 drugs?

A

abciximab (ReoPro)
tirofiban (Aggrastat)
eptifibatide (Integrilin)

(p. 616)

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