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NAPLEX 2023 > Chapter 34: Anticoagulation > Flashcards

Chapter 34: Anticoagulation Flashcards

1
Q

Coagulation involves activation of ____ & ____

A

Platelets
the clotting cascade

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2
Q

All of the clotting factors have an inactive and active form. Once activated, a clotting factor will activate the next clotting factor in the sequence until ___ is formed

A

fibrin

a = active

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3
Q

Which drugs are direct factor Xa inhibitors

A

rivaroXAban
apiXAban
edoXAban
betriXAban

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4
Q

Which drug is an indirect factor Xa inhibitor

A

Fondaparinux

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5
Q

Which drugs are IV direct thrombin inhibitors & which drug is an oral direct thrombin inhibitor

A

IV - argatroban, bivalirudin
PO- dabigatran

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6
Q

What are the major differences between warfarin and DOACs

A
  • DOACs = less DDI, less or comparable bleeding, and a shorter half-life compared to warfarin
  • DOACs are dosed based on the indication and kidney/liver function while warfarin is dosed based on INR
  • Use DOACs for stroke ppx in AFib if the CHA2DS2-VASc score is >/= 2 (men) or >/= 3 (women); BUT if there is moderate-severe mitral stenosis or mechanical heart valve, use WARFARIN
  • use DOACs in VTE prevetion except in anti-phospholipid syndrome use warfaring
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7
Q

Primary organization that publishes guidelines for anticoagulation

A

American College of Chest Physicians (CHEST)

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8
Q

Warfarin drug class

A

Vitamin K antagonist

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9
Q

Vitamin K is required for the carboxylation (activation) of which clotting factors

A

II, VII, IX and X

2, 7, 9, 10 - all inhibited by warfarin

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10
Q

INR is affected by many drugs and changes in

A

dietary vitamin K

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11
Q

UFH, LMWH, and fondaparinux MOA

A

work by binding to antithrombin (natural anticoag) –> increase activity of antithrombin –> inactivates thrombin (factor IIa) and other proteases (like factor Xa) involved in blood clotting & prevents the conversion of fibrinogen to fibrin

LMWH inhibit Xa > UFH
Fondaparinux is selective towards Xa

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12
Q

Direct thrombin inhibitors MOA

A

block thrombin directly (factor IIa), decreasing the amount of fibrin available for clot formation

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13
Q

Why are the IV direct thrombin inhibitors (argatroban and bivalirudin) clinically important?

A

They do not cross-react with HIT antibodies

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14
Q

What is the DOC once HIT develops in the hospital setting

A

IV argatroban

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15
Q

Dabigatran brand name

A

Pradaxa

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16
Q

Which organization requires policies and protocols to properly initiate and manage anticoagulant therapy

A

The Joint Commission’s National Patient Safety Goals

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17
Q

Which lab could signify that bleeding is occurring while on an anticoagulant

A

an acute drop in hemoglobin

≥ 2 g/dL

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18
Q

Which drugs/conditions can cause bruising

A

Chronic steroids, thrombocytopenia/clotting disorder, Cushing’s syndrome, malnutrition, fracture/sprain, infection

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19
Q

Which drugs/conditions can cause a hematoma

A

on abdomen from LMWH injection that was rubbed (do not rub), or an epidural or spinal hematoma in a patient using LMWH or DOAC who is given neuraxial anesthesia or a spinal punture

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20
Q

Esophageal bleeding occurs from

A

varices (bleeding veins, with liver cirrhosis), chronic reflux (esophagitis, Barrett’s)

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21
Q

How does duodenal bleeding occur

A

from ulcers (e.g., H. pylori-induced)

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22
Q

The farther the bleeding site is from the anus, the ___ (lighter/darker) the stool

A

darker

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23
Q

UFH prophylaxis of VTE dose

A

5000 units SC Q8-12H

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24
Q

UFH treatment of VTE dose

A

80 units/kg IV bolus; 18 units/kg/hr infusion

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25
Q

UFH treatment of ACS/STEMI dose

A

60 units/kg IV bolus; infuse 12 units/kg/hr

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26
Q

Which weight is used for dosing UFH & LMWH

A

TBW

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27
Q

UFH CI

A

uncontrolled active bleeding

hx of HIT, HSR pork

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28
Q

UFH side effects

A

bleeding (epistaxis, ecchymosis, gingival, GI), thrombocytopenia, HIT, hyperkalemia

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29
Q

UFH monitoring

A

aPTT or anti-Xa level, platelets, Hgb, Hct

check 6h after initiation & q6h until therapeutic

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30
Q

When should you check aPTT level while using UFH

A

6 hours after initiation and every 6 hours until therapeutic

then q24h

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31
Q

What is the therapeutic range of aPTT

A

1.5-2.5 x control

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32
Q

A decrease in platelets > __% from baseline suggests HIT

A

50%

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33
Q

UFH antidote

A

protamine

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34
Q

Continuous IV infusions are common for treating VTE and ACS because heparin has

A

a very short half-life

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35
Q

What is HepFlush used for

A

to keep IV lines open

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36
Q

UFH warnings

A

Fatal medication errors, especially in neonates, occurred when the incorrect heparin strength (higher dose) was chosen

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37
Q

The anti-factor ___ activity in LMWH is much greater than the anti-factor __ activity

A

Xa
IIa

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38
Q

Enoxaparin ppx of VTE dose & dose if CrCl < 30 mL/min

A
  • 30 mg SC Q12H or 40 mg SC daily

- CrCl < 30 mL/min: 30 mg SC daily

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39
Q

Enoxaparin treatment of VTE and UA/NSTEMI & dose if CrCl < 30 mL/min

A

1 mg/kg SC Q12H
(or 1.5 mg/kg SC daily only for inpatient VTE treatment)
-CrCl < 30 mL/min: 1 mg/kg SC daily

using TBW

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40
Q

LMWH treatment for STEMI in patients:
< 75 years
CrCl < 30 mL/min

A
  • 30 mg IV bolus plus a 1 mg/kg SC dose (then 1mg/kg q12h)
  • CrCl < 30 mL/min: 30 mg IV bolus plus a 1 mg/kg SC dose (then 1mg/kg qd)

using TBW

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41
Q

LMWH treatment for STEMI in patients:

> 75 years

A
  • > 75 years: NO bolus (0.75 mg/kg q12h)
  • CrCl < 30 mL/min: 1 mg/kg SC daily
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42
Q

LMWH CI

A

Hx of HIT, active major bleed

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43
Q

LMWH boxed warnings

A

risk of hematomas and subsequent paralysis with neuraxial anesthesia (epidural, spinal)

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44
Q

LMWH side effects

A

Bleeding, anemia, injection site rxns (e.g., pain, bruising, hematomas), ↓ platelets

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45
Q

____ level monitoring is recommended in pregnancy with LMWH

A

Anti-Xa

no monitoring required in most patients

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46
Q

Obtain peak anti-Xa levels __ hours post SC dose for enoxaparin

A

4

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47
Q

LMWH antidote

A

protamine

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48
Q

T/F: the air bubble from LMWH syringe should be expelled

A

False (can cause loss of drug)

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49
Q

HIT is an immune-mediated __ drug reaction that has high risk of venous and arterial thrombosis.

A

IgG

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50
Q

If left untreated, HIT can lead to a ____ state causing many complications including heparin-induced thrombocytopenia and thrombosis (HITT). HITT leads to amputation, post-thrombotic syndrome and/or death.

A

prothrombic

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51
Q

How is a diagnosis of HIT made

A

an unexplained drop in platelet count (>50% drop from baseline)

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52
Q

If a patient is on warfarin and diagnosed with HIT, what should be done

A

d/c the warfarin and administer Vitamin K

wait until Plts > 150,000 before restarting

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53
Q

In patients with HIT, which anticoags are recommended

A

non-heparin anticoagulants (in particular, argatroban)

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54
Q

In a patient with HIT, warfarin should not be started until the platelets have recovered to

A

≥ 150,000/mm3

overlap with non heparin AC

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55
Q

In patients with HIT, what is the preferred anticoag if urgent cardiac surgery or PCI is required

A

bivalirudin

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56
Q

Fondaparinux is a synthetic ____

A

pentasaccharide

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57
Q

Apixaban brand name

A

Eliquis

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58
Q

Rivaroxaban brand name

A

Xarelto

59
Q

If taking rivaroxaban 15 mg BID and miss a dose, how can it be taken?

A

two 15 mg tabs taken at once (take immediately together to ensure intake of 30 mg/day)

then resume regular schedule

60
Q

Apixaban dosing for nonvalvular AFib (stroke ppx)

A

5 mg BID

2.5 mg BID if patient has at least 2 of the following:
- age ≥ 80
- ≤ 60 kg
- SCr ≥ 1.5 mg/dL

61
Q

Apixaban dosing for treatment of DVT/PE

A

10 mg PO BID x 7 days, then 5 mg PO BID

62
Q

Rivaroxaban doses ≥ ___mg must be taken with food

A

15 mg

63
Q

Rivaroxaban dosing for treatment of DVT/PE
& dosing for CrCl < 30 mL/min

A
  • 15 mg PO BID x 21 days, then 20 mg PO daily
  • Avoid use in CrCl < 30 mL/min
64
Q

When should edoxaban dosing for nonvalvular AFib (stroke ppx) be avoided

A

CrCl > 95 mL/min

65
Q

Treatment of DVT/PE with edoxaban should be started after ___-___ days of parenteral anticoagulation

A

5-10 days

66
Q

Boxed warning for all DOACs, fondaparinux, oral direct thrombin inhibitors & LMWH

A

patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis

67
Q

Boxed warning for Edoxaban only

A

reduced efficacy in nonvalvular AFib patients with CrCl > 95 mL/min

68
Q

DOACs are not recommended with

A

prosthetic heart valves or antiphospholipid syndrome

69
Q

T/F: DOACs do not require monitoring of efficacy

A

True

70
Q

What is the antidote for apixaban and rivaroxaban

A

andexanet alfa (Andexxa)

71
Q

Fondaparinux CI

A

CrCl < 30 mL/min

72
Q

Avoid use of apixaban & rivaroxaban with strong dual inducers of ____ & ____

A

CYP3A4 and P-gp (e.g, carbamazepine, phenytoin, rifampin, St. John’s Wort)

73
Q

Avoid use of rivaroxaban with strong inhibitors of ____ & ____

A

3A4 and P-gp (e.g., ketoconazole, itraconazole, lopinavir/ritonavir, ritonavir, indinavir and conivaptan)

74
Q

Converting from warfarin to another oral anticoagulant

A

Remember: READ

  • Rivaroxaban when INR is < 3
  • Edoxaban when INR is ≤ 2.5
  • Apixaban when INR is < 2
  • Dabigatran when INR is < 2
75
Q

Converting from an oral Xa inhibitor (apixaban, edoxaban, and rivaroxaban) to warfarin:

A
  • Stop Xa inhibitor. Start parenteral anticoagulant and warfarin at next scheduled dose
76
Q

Converting from dabigatran to warfarin:

A

Start warfarin 1-3 days before stopping dabigatran

refer to dabigatran labeling for details

77
Q

What should be done if one misses a dose of dabigatran

A

Take immediately unless it is within 6 hours of next scheduled dose

78
Q

Dabigatran should be started for DVT/PE treatment __-__ days after starting parenteral anticoagulation

A

5-10

79
Q

Dabigatran CI

A

mechanical prosthetic heart valve

80
Q

Dabigatran SE

A

Dyspepsia, gastritis-like sx, bleeding (including GI bleeding)

81
Q

T/F: dabigatran does not require monitoring of efficacy

A

True

82
Q

Dabigatran should be dispensed ____ and discard ___ months after opening

A

in its original container
4

83
Q

T/F: dabigatran capsules should not be broken, chewed, crushed or opened

A

True

84
Q

Dabigatran should not be administered via

A

NG tube

85
Q

Argatroban and bivalirudin are used in patients at risk for ___

A

HIT

86
Q

Warfarin MOA

A

Competitively inhibits the C1 subunit of the VKORC1 enzyme complex, thereby reducing the regeneration of vitamin K epoxide and causing depletion of active clotting factors II, VII, IX and X and proteins C and S

87
Q

Warfarin brand name

A

Coumadin and Jantoven

88
Q

Which enantiomer of warfarin is more potent

A

S-enantiomer

89
Q

Warfarin dosing for healthy outpatients

A

≤ 10 mg daily for first 2 days, then adjust dose per INR values

90
Q

Lower doses of ≤ 5 mg of warfarin are indicated for which patients

A

elderly, malnourished, taking drugs which can ↑ warfarin levels, liver disease, HF, or have a high risk of bleeding

91
Q

Warfarin CI

A

Pregnancy (except with mechanical heart valves at risk for thromboembolism)

92
Q

Warfarin warnings

A

Tissue necrosis/gangrene, HIT, presence of 2C9*2 or *3 alleles and/or polymorphism of VCORC1 gene may increase bleeding risk

93
Q

Warfarin SE

A

Bleeding/bruising, skin necrosis, purple toe syndrome

94
Q

What is the goal INR of warfarin for most indications (DVT, AFib, biprosthetic mitral valve, mechanical aortic valve, antiphospholipid syndrome)

A

2-3

95
Q

What is the goal INR of warfarin for high-risk indications such as a mechanical mitral valve or 2 mechanical heart valves

A

2.5-3.5

96
Q

Warfarin antidote

A

Vitamin K

97
Q

Warfarin tablet colors

A
  • Remember: Please Let Greg Brown Bring Peaches To Your Wedding*
  • Pink (1mg)
  • Lavender (2 mg)
  • Green (2.5 mg)
  • Brown/Tan (3 mg)
  • Blue (4 mg)
  • Peach (5 mg)
  • Teal (6 mg)
  • Yellow (7.5 mg)
  • White (10 mg)
98
Q

Which foods are high in vitamin K

A
  • Broccoli
  • Brussel sprouts
  • Cabbage
  • Spinach
  • Tea
99
Q

Warfarin is a substrate of CYP

A

2C9

interactions with 2C9 have greatest impact on warfarin

100
Q

Which drug can cause a large decrease in INR

A

rifampin

101
Q

When starting amiodarone, the dose of warfarin should be decreased by

A

30-50%

102
Q

Which key drugs can increase INR

A

Amiodarone, fluconazole, metronidazole, TMP/SMX

103
Q

Which dietary supplement can decrease effectiveness of warfarin

A

St. John’s Wort

2C9 inducer

104
Q

Which dietary supplement can increase the bleeding risk of warfarin

A
  • “The 5 Gs”: garlic, ginger, gingko, ginseng, glucosamine
  • High doses of fish oils, willow bark and wintergreen oil
105
Q

In patients with acute DVT/PE, start warfarin on the same day as the parenteral anticoagulant (e.g., enoxaparin or UFH) and continue anticoagulants for a minimum of __ days and until the INR is > __ for at least __ hrs. Both criteria must be met

A

5
2
24

106
Q

For patients with consistently stable INRs on warfarin therapy, INR testing can be done up to every __ weeks rather than every 4 weeks

A

12

107
Q

Antidote for LMWH/UFH reversal

A

Protamine sulfate

108
Q

For IV UFH reversal, 1 mg of protamine will reverse ~__ units of heparin

A

100

109
Q

Since UFH has a very short half-life, reverse the amount of heparin given in the last __-__ hours; max dose __ mg

A

2-2.5h
50 mg

110
Q

For LMWH (enoxaparin) reversal, __ mg of protamine per __ mg of enoxaparin

A

1:1

111
Q

What is the antidote for dabigatran reversal

A

Idarucizumab

112
Q

Idarucizumab brand name

A

Praxbind

113
Q

Antidote for apixaban and rivaroxaban reversal

A

Andexanet alfa

114
Q

Andexanet alfa brand name

A

Andexxa

115
Q

Vitamin K or phytonadione brand name

A

Mephyton

116
Q

Vitamin K or phytonadione BW

A

hypersensitivity reactions

117
Q

Why is the SC and IM route of Vitamin K not recommended

A
  • SC: variable absorption
  • IM: risk of hematoma

use PO or IV

118
Q

Warfarin antidotes for reversal

A

Vitamin K or phytonadione, Kcentra, NovoSeven RT

119
Q

Factor VIIa Recombinant brand name

A

NovoSeven RT

120
Q

KCentra must be administered with

A

Vitamin K

121
Q

KCentra contains

A

Factors II, VII, IX, X, Protein C, Protein S

122
Q

IV injection of Vitamin K must be

A

infused slowly

123
Q

Vitamin K oral dose range

A

2.5-5 mg

124
Q

What to do with Vitamin K if INR is above therapeutic range but < 4.5 without bleeding

A

Reduce or skip warfarin dose. Monitor INR

125
Q

What to do with Vitamin K if INR is 4.5-10 without bleeding

A

Routine use of vitamin K is not recommended if no evidence of bleeding. Hold 1-2 doses of warfarin

126
Q

What to do with Vitamin K if INR is >10 without bleeding

A

Hold warfarin. Give oral vitamin K 2.5-5 mg even if not bleeding

127
Q

What to do with vitamin K if patient has major bleeding from warfarin

A

Hold warfarin therapy. Give vitamin K 5-10 mg by slow IV injection and four-factor prothrombin complex concentrate (PCC)

128
Q

Stop warfarin therapy approximately __ days before major surgery

A

5

129
Q

In patients with a mechanical heart valve, AFib or VTE at high risk for thromboembolism, bridging therapy with ___ or ___ is recommended

A

LMWH or UFH

130
Q

D/c therapeutic-dose SC LMWH __ hrs before surgery

A

24

131
Q

DVTs can be diagnosed with

A

an ultrasound

132
Q

RF for the development of VTE

A
  • Acute medical illness, Immobility, Previous VTE
  • Cancer or chemo
  • Pregnancy and postpartum period
  • Estrogen-containing meds or SERMs
  • EPO-stimulating agents
  • Obesity
  • surgery, trauma
  • Inherited or acquired thrombophilia (e.g., antithrombin deficiency, Factor V Leiden, antiphospholipid syndrome, Protein C or S deficiency)
133
Q

Any VTE that is caused by surgery or a reversible risk factor should be treated for __ months

A

3

134
Q

For pts without cancer, which drugs are preferred over warfarin for the first 3 months of tx for a DVT in the leg or a PE

A

dabigatran and the oral Factor Xa inhibitors (rivaroxaban, apixaban and edoxaban)

135
Q

for cancer patients what oral anticoagulants should be used

A

Factor Xa inhibitors are preferred

136
Q

Patients with mechanical heart valves have the highest risk for clotting/strokes and are treated with

A

warfarin

137
Q

Anticoagulation for patients with AFib who will undergo cardioversion:
* AFib > 48 hrs or unknown duration: anticoagulation (if warfarin, target INR 2-3) for at least __ weeks prior to and __ weeks after cardioversion when normal sinus rhythm is restored

A

3
4

138
Q

Anticoagulation for patients with AFib who will undergo cardioversion:
• AFib = 48 hrs duration undergoing elective cardioversion: start full therapeutic anticoagulation at presentation, do cardioversion, and continue full anticoagulation for at least __ weeks while pt is in normal sinus rhythm

A

4

139
Q

CHA2DS2-VASc Scoring System

A 
C – CHF…………………………………………………1
H - HTN…………………………………………………1
A – Age > 75 years …………………………….2
D – Diabetes ………………………………………..1
S2 – Prior stroke/TIA ………………………….2
V – Vascular Disease…………………………..1
(prior MI, PAD, aortic plaque)
A – Age 65-74 years …………………………..1
S – Sex category, female…………………….1
140
Q

HAS-BLED scoring system

A

H - HTN (1)
A - abnormal liver or kidney fxn (1-2)
S - prior stroke (1)
B - bleeding tendency or predisposition (1)
L - labile INR (if on warfarin) (1)
E - elderly (> 65 years) (1)
D - drugs (asa, NSAIDs), excessive alcohol use (1-2)

141
Q

Which CHA2DS2-VASc Score indicates oral anticoagulation is recommended. DOACs recommended over warfarin

A 
≥ 2 in males
≥ 3 in females
142
Q

Where should lovenox be injected

A

abdomen

143
Q

Important counseling point for lovenox

A

do not rub the site of injection

NAPLEX 2023 (88 decks)

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