Anticoagulation Flashcards
1
Q
Why are anticoagulants used for venous circulation?
A
Blood is faster moving and thrombi are composed of platelets and little fibrin ( as in arteries)
2
Q
Example of a Vit K antagonist
A
Warfarin / Acenocoumarol / Phenidione
3
Q
Onset of action for Warfarin
A
48-72 hours
4
Q
If an immediate effect of Warfarin is needed what does the BNF suggest we do?
A
Bridge with LMWH for 5 days or until INR >2
5
Q
What 2 conditions can Warfarin not be used in?
A
Cerebral artery thrombus and peripheral artery occlusion (first line = aspirin)
6
Q
Target INR for treatment of DVT / PE
A
2.5
7
Q
Target INR for AF
A
2.5
8
Q
Target INR for dilated cardiomyopathy
A
2.5
9
Q
Target INR for MI
A
2.5
10
Q
Target INR for recurrent DVT / PE
A
3.5
11
Q
Target INR for prosthetic heart valves
A
3.5
12
Q
Duration of Warfarin treatment in provoked VTE
A
3 monthd
13
Q
Duration of Warfarin treatment in isolated calf DVT
A
6 weeks
14
Q
Duration of Warfarin treatment in unprovoked DVT /PE
A
3 months (6 months to long term possible)
15
Q
Duration of Warfarin treatment in AF / Heart valves
A
Long term
16
Q
What does the BNF suggest doing to Warfarin if there is haemorrhage?
A
Check INR, Omit dose if necessary, consider reversal agents
17
Q
If a patient has a major bleed on warfarin what does the BNF suggest to do?
A
- stop warfarin 2. Phytomenidione by slow IV 3. dried prothrombin complex / fresh frozen plasma
18
Q
If a patients INR is >8 and they are on Warfarin what do you do?
A
Stop warfarin, give phytomenidione and repeat if INR is still too high. Restart Warfarin when INR < 5
19
Q
If a patient has an INR of 5-8 with no bleeding on Warfarin - what do you do?
A
Omit warfarin for 1 to 2 doses
20
Q
How many days before surgery should Warfarin be stopped?
A
5 days
21
Q
If you have a Warfarin patient where surgery cannot be delayed and INR >1.5 what do you do?
A
- If can delay for 6 - 12 hours give IV Vit K
2. If cant delay dried prothrombin complex + Vit K + check INR
22
Q
Benefit of Heparin
A
Short half life so can be terminated quickly
23
Q
Benefit of LMWH
A
Lower risk of osteoporosis + HIT, no standard montioring, OD dosing
24
Q
What anticoagulation medication can be used if a patient has HIT?
A
- Danaparoid - used for HIT patients
- Argatroban - can be started when thrombocytopenia has resolved
- Fondaparinux
25
Dose of apixaban for stroke prevention in NVAf
5mg BD longterm, reduce to 2.5mg BD if patient has 2 of the 3 factors
26
When would you reduce the dose of Apixaban when treating for stroke prevention?
If the patient is 1. >80 2. <60kg 3.Cr >133
27
Treatment dose of Apixaban
10mg BD for 7 days, reduce to 5mg BD for at least 3 months
28
Dose of Apixaban for prevention of recurrent DVT / PE
2.5mg BD
29
Dose of Apixaban for prevention of VTE in hip replacement
2.5mg BD after 12 to 24 hours of surgery. Treat for 32-38 days
30
Dose of Apixaban for prevention of VTE in knee replacement
2.5mg BDafter 12 to 24 hours of sugery for 10 - 14 days
31
At what renal function is Apixaban contraindicated?
CrCl<15 ml/min
32
Dose of Dabigatran for prevention of VTE in hip replacement
220mg OD for 28 to 35 days
33
Dose of Dabigatran for prevention of VTE in knee replacement
220mg OD for 10 days
34
Dose of Dabigatran for prevention of VTE in stroke prophylaxis
150mg BD (reduce to 110mg BD if >80 or on verapamil/amiodarone)
35
Treatment dose of Dabigatran for VTE
150mg BD for at least 3 months
36
At what CrCL is Dabigatran contraindicated?
<30ml/min
37
MHRA warning for DOACS
Increased risk of thrombotic events if patient has antiphospholipid syndrome
38
Reversal agent for Dabigatran
Idarucizumab
39
Dose of Edoxaban in stroke prophylaxis
60mg OD for long term
40
Dose of Edoxaban for treatment of DVT / PE
Post 5 days of parenteral, give 60mg OD for at least 3 months
41
Whst is the creatinine cut off for Edoxaban?
Crcl <15 ml/min
42
How should Rivaroxaban be taken?
With food
43
Dose of Rivaroxaban for prevention of VTE in hip replacement
10mg OD starting 6 to 10 hours post surgery for 35 days
44
Dose of Rivaroxaban for prevention of VTE in knee replacement
10mg OD starting 6 - 10 hours post surgery for 14 days
45
Dose of Rivaroxaban for prevention of stroke in NVAF
20mg OD longterm
46
Dose of Rivaroxaban in treatment of DVT or PE
15mg BD for 3 weeks then 20mg OD for at least 3 months
47
Dose of Rivaroxaban for prevention in recurrent DVT/PE
15mg BD for 3 weeks followed by 20mg OD for 3 months
48
Dose of Rivaroxaban in prevention of atherothrombotic events post ACS
2.5mg BD (+aspirin) for 12 months
49
What is the CrCl cut off for Rivaroxaban?
CrCl<15 ml/min
50
Antidocte for apixaban / Rivaroxaban
Andexant aloha (recombinant human factor Xa)
51
What is the mechansim of action behind antiplatlet drugs?
Reduce platelet aggregation and inhibit thrombus formation in arteries
52
Examples of antiplatlet drugs
Aspirin, Clopidogrel, Ticagrelor
53
If a patient has an NSTEMI how long should clopidogrel be given for?
3 months (+ aspirin)
54
If a patinet has a STEMI how long should Clopidogrel be given for?
4 weeks ( + low dose aspirin)
55
Contraindications for Aspirin
< 16 years ( Reyes syndrome risk), active peptic ulceration,haemophillia
56
Features of Aspirin overdose
Tinnitus, deafness, vasodilation, hyperventilation, sweating
57
In adults, when no strength is stated what should be dispensed?
300mg aspirin tablets
58
How many aspirin can be sold OTC?
pack size of 32 capsules or tablets. Pharmacists can sell up to 100 caps or tablets in justifiable circumstances
59
Warning labels for Aspirin
Take with food, Contains aspirin, Do not crush or chew
60
How many days before elective surgery should Clopidogrel be stopped?
7 days
61
Why do dipyridamole capsules need to be dispensed in the original container?
They contain desiccant in the pack . Any remaining capsules should be discarded after 6 weeks
62
Maximum dose of Edoxaban if given alongside Dronedarone/Ciclosporin/ erythromycin etc
30mg OD
63
MHRA alert for Rivaroxaban
1. DOACs + risk of antiphospholipid syndrome
| 2. Must be taken with food to increase efficacy
64
At what body weight is Rivaroxaban cautioned?
<60kg
65
What medication can be used as an adjunct to thromboprophylaxis associated with prosthetic valves
Dipyramidole (MR preparation are licensed for secondary prevention of ischemic stroke + TIA)
66
When is prasugrel + aspirin or Ticagrelor + aspirin used in combination and for how long?
prevention of atherosclerotic events in patients with ACS for 12 months
67
When is Cangrelor used?
In combination with aspirin for the reduction in thrombotic cardiovascular events in patients with CAD undergoing PCI who have not received treatment wiht oral clopidogrel,prasugrel or Ticagrelor and in whom these drugs are not suitable
68
What antiplatlet therapy is required for patients who are selected for PCI with the placement of a coronary stent?
DAPT (asprin + clopi/ticagrelor/prasugrel/cangrelor)
| Aspirin should continue indefinitely
69
Following PCI, how long should a patient with a bare-metal stent receive clopidogrel for?
1 month
70
Following PCI, how long should a patient with a drug elluting-metal stent receive clopidogrel for?
6 months
71
How do Glycoprotein IIb/IIA inhibitors work?
prevent platelet aggregation by blocking the binding of fibrinogen to receptors on platelets
72
Examples of Glycoprotein IIb/IIa inhibitors
Abciximab, Eptifibatide, Tirofiban
73
What is Abiciximab licensed for?
as an adjunct to heparin (unfractionated) and aspirin for the prevention of ischemic complications in highrisk patients undergoing PCI. Abiciximab should be used ONCE only
74
What are Tirofiban and Eptifibatide licensed for?
prevent early MI in patients wiht unstable angina or NSTEMI
75
What dose of Clopidogrel is given for prevention of atherosclerotic events in PCI?
300mg STAT prior to procedure
76
What dose of Clopidogrel is suggested for prevention of atherosclerotic events in ACS (NSTEMI)
300mg STAT, 75mg OD for 12 months
77
What dose of Clopidogrel is suggested for prevention of atherosclerotic events in ACS (STEMI)
300mg STAT, 75mg OD for 4 weeks at least
78
What are the signs of Heparin induced thrombocytopenia?
30% reduction in platelet count, skin allergy, thrombosis. Stop heparin, use an alternative anticoagulant e.g. Danaparoid
79
How can heparin cause hyperkalaemia
Inhibition of aldosterone secretion
80
What patients are more at risk of hyperkalaemia from Heparin?
Patient with diabetes, chronic renal failure, raised plasma potassium, taking potassium sparring drugs
81
If anti-factor Xa levels are needed, when should they be taken?
3 to 4 hours post dose ( aim for anti-factor Xa 0.5-1unit/mL)
82
Dose of Enoxaparin for tx of DVT if <50kg
40mg BD
83
Dose of Enoxaparin for tx of DVT if 50 - 69kg
60mg BD
84
At what CrCl should Tinzaparin be avoided
<30ml/min
85
What is urokinase most commonly used for?
Occluded central venous catherters (blocked by fibrin clots)
86
What class of anticoagulants can direct acting antivirals interact with (MHRA alert)
Vitamin K antagonists - risk of changes to INR monitor closely
87
What anticoagulant is teratogenic?
Warfarin - warned women of child bearing potential about the risks
88
Why should patients be warned to contact their Drs if they develop a painful skin rash on warfarin?
MHRA alert - risk of calciphylaxis with Warfarin. Most commonly observed in patients wiht known risk factors e.g. end stage renal disease
