Anticoagulation Flashcards
1
Q
What’s anticoagulant NOT used for?
A
They don’t break down existing clots (that’s done by drugs such as tissue plasminogen activator - tPA).
2
Q
What dx states are anticoagulants used for?
A
Prevention and tx of DVT/PE
Prevention of stroke
Tx of acute coronary syndrome (ACS)
3
Q
How many pathways are in the coagulation cascade? Name them
A
2 pathways
Contact activation pathway (Intrinsic pathway)
Tissue factor pathway (Extrinsic pathway)
4
Q
List the factors in the intrinsic pathway
A
XII, XI, IX, VIII, X, V
5
Q
List the factors in the extrinsic pathway
A
Tissue factor and VII
6
Q
List the main risk factors for the development of venous thromboembolism. (U)
A
Surgery
Major trauma
Immobility
Cancer
Previous venous thromboembolism
Pregnancy
Estrogen-containing medications or selective estrogen receptor modulators
7
Q
MOA of UFH, LMWH and fondaparinux? (U)
A
Bind to antithrombin (AT) -> increases AT activity 1,000 fold
8
Q
Effect of antithrombin (AT)? (U)
A
AT Inactivates thrombin and other proteases involved in blood clotting, including factor Xa.
9
Q
Which anticoagulant specifically inhibits factor Xa?
A
LMWHs
10
Q
How does fondaparinux work?
A
Requires AT binding to selectively inhibit Factor Xa
11
Q
What’s the brand name of fondaparinux?
A
Arixtra
Synthetic pentasaccharide
12
Q
MOA of direct thrombin inhibitors? (U)
A
Blocks thrombin directly -> decreasing the amt of fibrin available for clot formation
13
Q
What’s the importance of direct thrombin inhibitors and heparin-induced thrombocytopenia (HIT) antibodies? (U)
A
Direct thrombin inhibitors don’t cross-react with HIT antibodies
14
Q
Therefore, what’s the drug of choice when HIT develops from the use of UFH (and less commonly, LMWHs)? (U)
A
Direct thrombin inhibitors e.g. argatroban
15
Q
Does Dabigatran (Pradaxa - direct thrombin inhibitor) require blood test to monitor effectiveness? (U)
A
No.
16
Q
Advantages of Dabigatran (pradaxa) over warfarin?
A
Pradaxa doesn’t require blood tests
Not subjected to food interactions
Has fewer drug interactions than warfarin
17
Q
Disadvantages of Dabigatran (Pradaxa)?
A
Significant dyspepsia/gastritis
Increased risk of GI bleed
18
Q
List agents that work by inhibiting factor Xa?(u)
A
Rivaroxaban (Xarelto)
Apixaban (Eliquis)
19
Q
What meds should not be used in pts with prosthetic heart valves? (U)
A
Dabigatran (Pradaxa)
Rivaroxaban (Xarelto)
Apixaban (Eliquis)
20
Q
MOA of warfarin?(u)
A
Vitamin K antagonist
21
Q
Role of vitamin k in clotting factors? (U)
A
Vit k is req for the carboxylate on of clotting factors II, VII, IX, and X.
22
Q
What body requires implementation of policies and protocols to properly initiate and manage anticoagulant therapy? (U)
A
The Joint Commission’s National Patient Safety
23
Q
What’s HIT?
A
Immune-mediated (IgG) drug reaction -> forms antibodies against heparin when it binds to platelet factor 4 (PF 4) -> then binds to Fc receptors on platelets, -> further platelet activation
24
Q
What’s the result of untreated Heparin-induced thrombocytopenia (HIT)?
A
Pro-thrombotic state causing many complications such as venous and arterial thrombosis (HITT)
25
What's the typical onset of HIT?
5-14 days after the start of heparin
OR
Within hours if a pt has been recently exposed to heparin (within last 3 months)
26
Howz HIT diagnosed? (U)
Profound, unexplained drop in platelet count (> 50%) from baseline
27
If HIT is suspected, what should be done if pt is on UFH or LMWH?
Stop all forms of UFH and LMWH, even heparin flushes and heparin-coated catheter
28
If HIT is suspected, what should be done if pt is on warfarin?
Stop warfarin and start Vit K
29
What med is recommended in pts with HIT?
Argatroban
30
When should warfarin be re-started after HIT?
When platelet is at least 150,000/mm3
31
At what dose should warfarin be initiated and how?
Max. of 5mg
Overlap with non-heparin anticoagulant for a minimum of 5 days until INR is within target for 24 hrs
32
What's preferred anticoagulant in pts that req urgent cardiac surgery or PCI?
Bivalirudin
33
MOA of UFH?
Binds to antithrombin (AT)
Inactivates thrombin (Factor IIa) & factor Xa (as well as factors IXa, XIa, XIIa and Plasmin)
Prevents the conversion of fibrinogen to fibrin
34
What's the usual infusion rate of UFH for tx? Concentration?
25,000 units in 250ml in D5W (or 1/2 NS or NS)
100units/ml
35
What's tne strength of UFH used in line flush (HepFlush)?
10 units/mL, 100units/mL
36
Uses of heparin "lock-flushes" (Hep-Flush)
Used to keep IV lines open
Note: there's been fatal errors from choosing incorrect heparin strength
37
What's the dose of UFH for prophylaxis of VTE?
5,000 units SC Q8-12H
38
What's used when using UFH for tx of ACS/STEMI, adjusted body weight or actual body weight?
Actual body weight
39
What's the antidote of UFH? Dosing? Max dose?
Protamine
1mg of protamine per 100 units of UFH
Max dose - 50mg
40
Which UFH pdts contain black box warnings? Why?
Some heparin pdts contain benzyl alcohol.
Theses pdts are contraindicated in neonates and infants
41
SE of UFH?
Bleeding (epistaxis, ecchymosis, gingival, GI etc)
Thrombocytopenia
Heparin induced thrombocytopenia (HIT)
Hyperkalemia
Osteoporosis (with long- pterm use)
42
What SE of UFH is associated with long-term use of UFH?
Osteoporosis
43
Howz UFH monitored?
aPTT
OR
anti-Xa level: 0.3-0.7 units/mL
44
How often is aPPT monitored when pt is on UFH?
6hrs after initiation and Q 6hrs until the therapeutic range of 1.5-2.5 x control
45
What's the therapeutic range of aPTT?
1.5-2.5 x control (pts baseline)
46
What other parameters are monitored when a pt is on UFH? How often?
Platelet count
Hgb
Hct
These are monitored at BASELINE and DAILY to monitor for thrombocytopenia and bleeding
47
Why does UFH have an unpredictable anticoagulant response?
UFH has variable and extensive binding to plasma proteins and cells
48
List the agents that may increase clotting risk. What should be done when starting UFH?
Estrogen and SERMS and other anticoagulants
They should be discontinued if UFH is required
49
MOA of LMWHs?
Work similar to heparin except that the inhibition is much greater for Factor Xa than Factor IIa
50
List agents that are LMWHs.
Enoxaparin (Lovenox)
Dalteparin (Fragmin)
51
What's the brand name of Enoxaparin?
Lovenox
52
What's the dose of Enoxaparin (Lovenox) for prophylaxis of VTE?
30mg SC Q12H or 40mg SC daily
53
What's the dose of Enoxaparin (Lovenox) for prophylaxis of VTE if CrCl < 30mL/min?
30mg SC daily
54
What's the dose of Enoxaparin (Lovenox) for tx of VTE and UA/NSTEMI?
1mg/kg SC Q12H or 1.5mg/kg SC daily
55
What's the dose of Enoxaparin (Lovenox) for tx of VTE and UA/NSTEMI if CrCl < 30mL/min?
1 mg/kg SC daily
56
What's the dose of Enoxaparin (Lovenox) for tx of STEMI? In < 75yrs? Max dose?
< 75 yrs = 30mg IV bolus + 1 mg/kg SC dose followed by 1mg/kg SC Q12H
Max dose: 100mg for the 1st 2 doses ONLY
57
What's the dose of Enoxaparin (Lovenox) for tx of STEMI? In > 75yrs? Max dose?
0.7mg/kg SC Q12H (no bolus)
Max 75mg for the 1st 2 doses ONLY
58
What's the dose of Enoxaparin (Lovenox) for tx of STEMI in CrCl < 30mL/min?
1 mg/kg SC daily
59
What's the dose of Enoxaparin (Lovenox) for tx of STEMI in pts managed with percutaneous coronary intervention (PCI), if last dose was given 8-12 hrs before balloon inflation?
0.3 mg/kg IV bolus
60
What's the brand name of Dalteparin?
Fragmin
61
What's the black box warning Enoxaparin (Lovenox) and Dalteparin (Fragmin)?
Risk of hematomas and subsequent paralysis (for pts receiving neuraxial anesthesia - spinal epidural)
62
Contraindications to use of LMWHs (Enoxaparin - Lovenox; Dalteparin - Fragmin)?
Bleeding
Thrombocytopenia
Hyperkalemia
63
When is monitoring of LMWHs required? (U)
During pregnancy
And
Pts with mechanical heart valves
64
What's monitored during LMWHs use?
Peak anti-Xa levels 4 hours post dose
65
Is Factor Xa inhibitor derived from natural pdt?
Synthetic pentasaccharide
66
MOA of factor Xa inhibitors?
Selectively inhibits factor Xa via antithrombin (AT)
67
Is Fondaparinux a direct inhibitor of factor Xa?
No.
It inhibits Factor Xa via antithrombin (AT), therefore it's an INDIRECT inhibitor of Factor Xa
68
What's the brand name of Fondaparinux?
Arixtra
69
What's contraindication to the use of Fondaparinux (Arixtra)?
Severe renal impairment (CrCl < 30mL/min) (u)
Active major bleed
Bacterial endocarditis
Thrombocytopenia with tve test for anti-platelet antibodies in presence of fondaparinux
70
What's contraindication to the use of Fondaparinux (Arixtra) as prophylaxis?
Body weight < 50kg
71
What's the SE of fondaparinux (Arixtra)?
Bleeding (epistaxis, ecchymosis, gingival, GI etc) (u)
Local inj site rxns (rash, pruritus, bleeding)
Thrombocytopenia
Anemia
Nausea
72
List agents under Factor Xa inh?
Fondaparinux (Arixtra)
Rivaroxaban (Xarelto)
73
What's the brand name for Rivaroxaban?
Xarelto
74
When can missed dose be doubled?
In pts receiving 15mg twice daily, t4 okay to take 2 tablets at once
75
Tx of non-valvular AFib with Rivaroxaban (Xarelto)? CrCl > 50mL/min? 15-50mL/min? < 15mL/min?
CrCl > 50mL/min: 20mg PO daily with EVENING meal
CrCl: 15-50mL/min: 15mg PO daily with EVENING meal
CrCl < 15mL/min: AVOID use
76
Tx of DVT/PE with Rivaroxaban (Xarelto)?
15mg PO bid WITH FOOD x 21 days then 20mg PO daily WITH FOOD
77
When should Tx of DVT/PE with Rivaroxaban (Xarelto) be avoided?
CrCl < 30mL/min
78
Dose of Rivaroxaban (Xarelto) for prophylaxis for DVT (after knee/hip replacement)
10mg PO daily WITHOUT regard to food
79
SE of Rivaroxaban (Xarelto)? (U)
Bleeding
80
What's the brand name of Apixaban?
Eliquis
81
The usual dose of Apixaban (Eliquis) is 5mg bid, when is it halved?
If you have at least 2 of the following:
Age >= 80yrs
Body weight =< 60kg
SCr >= 1.5mg/dL
Give 2.5mg bid
82
When is Apixaban (Eliquis) avoided?
CrCl < 15mL/min
83
Is there an antidote for Fondaparinux (Arixtra), Rivaroxaban (Xarelto), Apixaban (Eliquis)? Monitoring parameter?
No antidote
No monitoring of efficacy required
84
List agents of direct thrombin inhibitors (IV or SC)
Argatroban
Bivalirudin (Angiomax)
Desirudin (Iprivask)
85
List agents of direct thrombin inhibitors (Oral)
Dabigatran (Pradaxa)
86
What's the brand name of bivalirudin?
Angiomax
87
When's direct thrombin inhibitor (DTI) used?
In pts with a hx of HIT
88
Is there cross-reaction of DTI with HIT?
No. No cross rxn with HIT and argatroban, bivalirudin
89
Is there antidote for DTI?
No
90
What's the brand name for Dabigatran?
Pradaxa
91
How to use Dabigatran (Pradaxa)?(u)
Swallow capsules whole
Do not break, chew, crush or open
Do not out in NG tube
92
Howz Dabigatran (Pradaxa) stored?
Keep in original container
Discard 4 months after opening original container
Keep bottle tightly closed to protect from moisture (store in a cool dry place; not bathrooms)
93
SE of Dabigatran (Pradaxa)? U
Dyspepsia
Gastritis-like sx
Bleeding (including more GI bleed)
94
MOA of warfarin?
Competitively inhibits Vit K epoxide reductase (VKORC1) enzyme complex -> depletion of active clotting factors II, VII, IX, and X and proteins C and S
95
What's the brand name of warfarin?
Coumadin, Jantoven
96
Whats the composition of warfarin (Coumadin, Jantoven)?
Racemic mixture of R- and S- enantiomers with S-enantiomer being more potent
97
Howz warfarin (Coumadin/ Jantoven) dosed?
10mg for 1st 2 days, then adjust dose per INR (healthy outpatients)
Elderly - =<5mg
98
What's the color of 1mg warfarin (Coumadin/Jantoven)?
Pink
99
What's the color of 2mg warfarin (Coumadin/Jantoven)?
Lavender
100
What's the color of 2.5mg warfarin (Coumadin/Jantoven)?
Green
101
What's the color of 3mg warfarin (Coumadin/Jantoven)?
Tan
102
What's the color of 4mg warfarin (Coumadin/Jantoven)?
Blue
103
What's the color of 5mg warfarin (Coumadin/Jantoven)?
Peach
104
What's the color of 6mg warfarin (Coumadin/Jantoven)?
Teal
105
What's the color of 7.5mg warfarin (Coumadin/Jantoven)?
Yellow
106
What's the color of 10mg warfarin (Coumadin/Jantoven)?
White
107
SE of warfarin (Coumadin/Jantoven)?
Bleeding
Skin necrosis
Purple toe syndrome
108
What's the monitoring parameter of warfarin (Coumadin/Jantoven)?
INR - 2.0-3.0
109
What's the exceptions to monitoring parameter of warfarin (Coumadin/Jantoven)?
High risk indications e.g. Mechanical mitral valve or mechanical heart valves in both the aortic and mitral position
INR - 2.5-3.5
110
What's the pregnancy category for warfarin? Exception?
X
Women with mech heart valves - preg cat D
111
What's the antidote of warfarin?
Vit K
112
What's the exceptions to 4 weekly testing of the INR?
For pts consistently stable INR, testing can be done up to Q12 weeks
113
T/F? Warfarin is highly protein bound?
True
T4 caution with other highly protein bound drugs that may displace warfarin
114
Which 2C9 inducer causes a LARGE decrease in INR?
Rifampin
115
When should the dose of warfarin be decreased by 30-50%?
When starting Amiodarone
116
List the most common agents with pharmacodynamic interaction with warfarin.
NSAIDs (aspirin, ibuprofen, Celecoxib, etc)
Antiplatelet
Other anticoagulant
SSRIs and SNRIs
117
What's the caveat with the pharmacodynamic drug interaction of NSAIDs, other Antiplatelet, other anticoagulant, SSRIs and SNRIs with warfarin?
These increase bleeding risk BUT INR may be in the usual range or slightly elevated
118
What other med increases bleeding risk with no effect on the INR ?
Ginkgo biloba
119
What's forms of Vit k should be avoided? Why? U
SC inj of Vit k - has a slower onset and can produce variable result
IM inj of Vit k - due to risk of hematoma formulation
120
Which dosage form of Vit K is preferred (when a stat reversal is not required)? U
Oral Vit k (gen at doses of 2.5-5mg)
121
What other dosage form of Vit k is acceptable? Caveat to use?
IV Vit k
Infuse slowly bcuz of anaphylaxis rxn
122
List food high in Vit k
Broccoli, Brussels sprouts
Cabbage, Canola oil, Cauliflower, Chickpeas, Cole Slaw, Collard Greens, Coriander
Endive
Green kale
Lettuce (red leaf or butterhead)
Mustard greens
Parsley
Soybean oil, Spinach, Swiss chard
Tea (green or black), Turnip greens
Watercress
123
How to use Vit K in INR above therapeutic range BUT < 4.5?
Reduce or skip warfarin dose (no Vit k use)
124
How to use Vit K in INR 4.5-10 without bleeding?
Vit K not recommended.
Hold 1-2 doses of warfarin
125
How to use Vit K in INR > 10 without bleeding?
Hold warfarin
Give PO Vit k 2.5-5mg
Resume warfarin at lower dose when INR is therapeutic
126
How to use Vit K in pts with major bleeding from warfarin?
Hold warfarin
Give Vit k 5-10 mg by SLOW IV inj and four-factor prothrombin complex concentration (PCC)
Fresh frozen plasma (FFP) is not recommended
127
When's warfarin stopped before major surgery?
5 days before major surgery
128
Whats the exceptions to stopping warfarin 5 days b4 major surgery?
Mech heart valve
AFib
VTE at high risk of thromboembolism
D/c 24 hrs before surgery
129
What makes up CHADS2 scoring system?
```
C - CHF
H - HTN
A - Age (> 75)
D - Diabetes
S2 - prior stroke/ TIA
```
Each risk factor = 1, except stroke/TIA = 2
130
If pt has AFib > 48 hrs, what should be considered before cardioversion?
Target INR 2.0-3.0 should be at target for at least 3 weeks PRIOR to and 4 weeks AFTER cardioversion when normal sinus rhythm is restored
131
If pt has AFib =< 48 hrs, what should be considered before cardioversion?
Start full therapeutic anticoagulation at presentation, do cardioversion and continue full anticoagulation for at least 4 weeks while pt is in normal sinus rhythm
132
What's the antithrombotic therapy for pts with AFib with CHADS2 score = 0?
No therapy
81mg aspirin can be started for those pts wanting anticoagulant therapy
133
What's the antithrombotic therapy for pts with AFib with CHADS2 score = 1?
Oral anticoagulant (Dabigatran -Pradaxa 150mg bid is preferred anticoagulant)
134
What's the antithrombotic therapy for pts with AFib with CHADS2 score >= 2?
Oral anticoagulant (Dabigatran -Pradaxa 150mg bid is preferred anticoagulant)
135
What's options are available for those who can't receive anticoagulants?
Graduated compression stockings (GCS)
Intermittent pneumatic compression (IPC)
136
For Enoxaparin (Lovenox), what should be done with bubbles in the syringe? U
Don't expel air bubbles in the syringe prior to inj (unless your doctor has advised you to do so)
137
How should Dabigatran (Pradaxa) be used?
Swallow capsules whole
138
Howz Dabigatran (Pradaxa) stored?
Keep Dabigatran in original bottle or blister to keep it dry
Don't put Dabigatran in pill boxes or pill organizers
139
How should missed dose of Dabigatran be dealt with?
If next dose is LESS than 6 hours, skip the missed dose
Don't take 2 doses of Dabigatran at the same time
140
What med condition is Rivaroxaban (Xarelto) and Dabigatran (Pradaxa) not recommended for?
Not for pts with artificial heart valves
141
How should Rivaroxaban (Xarelto) be used for AFib?
1 time a day WITH EVENING meal
142
How should Rivaroxaban (Xarelto) be used for blood clot in the veins of legs and lungs?
Once or twice a day as prescribed WITH FOOD
143
If Rivaroxaban (Xarelto) is used 2 times a day, how can a missed dose be used?
You can take 2 doses at the same time
144
How should Rivaroxaban (Xarelto) be used for hip or knee surgery?
Take 1 Rivaroxaban (Xarelto) once daily WITH/WITHOUT food
145
What discoloration may occur with warfarin use?
Purple toe syndrome
146
What's the dose of Lovenox (Enoxaparin) used as a bridge with Warfarin?
Lovenox 80mg SC Q12H
147
List agents that don't increase bleeding risk, while on warfarin?
Calcium with Vit D
Fidaxomicin
148
What's the 1st line tx for a pt with DVT + hx of HIT?
Argatroban
149
What's anticoagulant used for?
To prevent blood clots from forming and to keep existing clots from becoming large or expanding
