Anticoagulation Flashcards Preview

Fall 2014 - Pharm Cardio > Anticoagulation > Flashcards

Flashcards in Anticoagulation Deck (51):
1

Steps of Normal Hemostasis

1. injury
2. vasospasm decreases blood flow, platelet aggregation
3. platelets form plug
4. coagulation activation = fibrin clot
5. clot removed by fibrinolysis

2

Virchow's Triad

-hypercoagulability
-vascular injury
-venous stasis (blood pooling)

3

What activates the clotting cascade? What inhibits the cascade?

-clotting factors activate
-anticoagulants inhibit

4

Unfractionated Heparin MOA

-inactivates thrombin and other clotting factors
-prevents conversion of fibrinogen to fibrin
-prevents coagulation

5

Indications for UFH

-venous thromboembolism tx and Px
-unstable angina
-acute MI
-coronary bypass surgery
-hemodialysis
-angioplasty
-IV line flushes

6

How does the half life of UFH change at different doses?

-half life increases with increasing doses

7

UFH AEs

-hemorrhage
-heparin induced and heparin associated thrombocytopenia
-osteoporosis and hyperkalemia w/ long term use

8

Heparin Induced Thrombocytopenia

-platelets < 100,000 or <50% baseline
-need to discontinue heparin if this occurs
-initiate alternative anticoagulation
-more worrisome than heparin associated thrombocytopenia

9

Heparin Associated Thrombocytopenia

-mild thrombocytopenia
-platelets rarely drop <100,000
-manage w/ observation

10

UFH Pregnancy Use

-category C, can be used

11

Dosing of UFH

-loading dose followed by continuous infusion
-can be given subQ for non-acute situations

12

Monitoring of UFH

-check aPTT at 6 hours and adjust dose as needed
-aPTT should be higher than the reference range

13

What should be given to reverse heparin?

protamine

14

LMWH MOA

-inhibit clotting factor Xa

15

How does the half life of LMWH compare to UFH?

-LMWH half life is longer so q12 hour dosing

16

What are the generic and trade names for LMWH?

-generic: enoxaparin
-trade: Lovenox

17

LMWH AEs

-hemorrhage
-thrombocytopenia: lower incidence of HIT than with heparin, check platelets on day 3
-injection site hematoma, minor bleeding
-osteoporosis

18

LMWH Monitoring

-routine monitoring not necessary
-antifactor Xa activity may be helpful in pts with low CrCl, morbid obesity, during pregnancy or therapy longer than 14 days

19

What should be given to reverse LMWH?

-protamine
-but it dose not neutralize anticoagulation of LMWH completely

20

Fondaparinux/Arixtra MOA

-inhibits factor Xa
-inhibits thrombin formation and thrombus development

21

What has limited the use of direct thrombin inhibitors?

-relatively high incidence of bleeding in clinical trials and high cost

22

Warfarin MOA

-vitamin K antagonist --> blocks production of vitamin K dependent clotting factors

23

Warfarin Indications

-venous thromboembolism tx and Px
-acute MI
-prosthetic heart valves
-atrial fib
-TIA/stroke
-hypercoagulable states
-peripheral arterial occlusive dz

24

Warfarin Absorption

-97-99% GI tract

25

Warfarin AEs

-hemorrhage
-skin necrosis (rare, appears early)
-purple toe syndrome (3-10 weeks after therapy start

26

Warfarin CIs

-pregnancy cat X
-pts with additional risks for hemorrhage
-noncompliance w/ drug therapy or monitoring
-alcoholism
-surgery, dental work
-spinal anesthesia or spinal injections

27

Warfarin Dosing

-qday, usually overlapped with heparin 4-5 days
-dosing very patient specific and available in many strengths

28

Warfarin Monitoring

-INR: international normalized ratio; established to standardize monitoring
-INR reference range about 1
-most goal ranges are 2.0-3.0 (up to 3.5 for prosthetic heart valve pts)

29

What should be given to reverse warfarin?

vitamin K or fresh frozen plasma

30

Warfarin Drug Interactions

-many; assume interaction until proven otherwise
-key ones: SMX, NSAIDs, aspirin

31

Warfarin Food Interactions

-foods with high amounts of vitamin K will antagonize warfarin (eg green veggies, MVI with vit K, other dietary supplements)

32

Effects of Alcohol on Warfarin:
1. Acute EtOH Ingestion
2. Chronic EtOH Ingestion
3. Cirrhosis

1. acute increases INR
2. chronic decreases INR
3. cirrhosis increases INR

33

Dabigatran/Pradaxa MOA

-direct thrombin inhibitor

34

Dabigatran/Pradaxa Indications

-thromboembolism (stroke) prevention in afib

35

Dabigatran/Pradaxa AE

-bleeding, GI complaints

36

Dabigatran/Pradaxa CI

-active, pathologic bleeding
-previous hypersensitivity reaction

37

What is the advantage of Dabigatran/Pradaxa over warfarin? Disadvantages?

-prevents 5 more strokes/1000 pts/yr
-causes more GI bleeding than warfarin
-$250/mo compared to 80/mo for warfarin
-no antidote

38

Rivaroxaban/Xarelto MOA

-oral factor Xa inhibitor

39

Rivaroxaban/Xarelto Indications

-thromboembolism (stroke) prevention in afib
-prevent thrombosis after knee or hip surgery

40

Rivaroxaban/Xarelto AE

-bleeding

41

Rivaroxaban/Xarelto CI

-active major bleeding
-hypersensitivity

42

Rivaroxaban/Xarelto AE and Costs Compared to Warfarin

-greater risk of GI bleeding than warfarin
-$230/mo compared to 80/mo for warfarin
-no antidote

43

Apixaban/Eliquis MOA

-oral factor Xa inhibitor

44

Apixaban/Eliquis Indications

-thromboembolism (stroke) prevention in afib
-prevent thrombosis after knee or hip surgery

45

Apixaban/Eliquis AE

-bleeding

46

Apixaban/Eliquis CI

-active pathologic bleeding
-hypersensitivity

47

What are the advantages of Apixaban/Eliquis over warfarin? Disadvantages?

-for every 1000 pts/yr, prevents more strokes, avoids more major bleeds and prevents more deaths than warfarin
-more expensive than warfarin
-no antidote

48

What are the options for prevention of VTE?

-heparin
-LMWH
-Fondaparinux
-graduated compression stockings

49

What are the options for treatment of VTE?

-parenteral anticoagulant and warfarin
-thrombolytics (generally not used)

50

VTE Parenteral Anticoagulant and Warfarin Treatment

-parenteral anticoag for 5-7 days: continuous infusion heparin, subQ UFH, LMWH, Fondaparinux
-warfarin therapy begins on day 1 after first dose of parenteral anticoag
-overlap parenteral and oral anticoag therapy x5 days
-must have therapeutic INR 2 days in a row before stopping heparin

51

CHADS2 Score

-CHF
-HTN
-Age > 75 years
-DM
-Stroke or TIA history (x2 points)