Anticoagulants Flashcards Preview

Oncology, haematology and palliative care > Anticoagulants > Flashcards

Flashcards in Anticoagulants Deck (42)
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1
Q

What are the two main indications for anticoagulants?

A

Treatment - vte (DVT/PE)

Prophylaxis - vte (DVT/PE/stroke)

2
Q

Describe how low molecular weight heparin works?

A

Factor Xa inhibitor

3
Q

How often is LMWH given and by what route?

A

OD/BD

SC

4
Q

Is monitoring required for LMWH?

A

no

Only in special situations check activated factor X levels

5
Q

What should you do to the dose of LMWH in renal failure?

A

Reduce if for prophylaxis

6
Q

How is unfractionated heparin given?

A

IV/SC

7
Q

Describe how unfractionated heparin works?

A

Binds to antithrombin III (endogenous inhibitor of coagulation). Increases its ability to inhibit thrombin, factor Xa and IXa

8
Q

Describe the speed of onset of unfractionated heparin

A

Fast onset

9
Q

How is unfractionated heparin monitored and dosed?

A

APTT

10
Q

List the side effects of both LMWH and UFH

A

Increased bleeding
Heparin induced thrombocytopenia (HIT)
Osteoporosis with long term use (less common in LMWH than UFH)
Hyperkalaemia

11
Q

Which side effects are less common in LMWH than UFH

A

HIT and osteoporosis

12
Q

What are the contraindications to heparins

A
Bleeding disorders
Platelets <60X10^9 
Previous HIT 
Peptic ulcer 
Cerebral haemorrhage 
Neurosurgery 
Severe hypertension
13
Q

Name some low molecular weight heparins

A

Dalteparin
Enoxaparin
Tinzaparin

14
Q

Describe the mechanism of action of warfarin

A

Inhibits the reductase enzyme and stops vitamin K being activated - creates a similar state to vit K deficiency

15
Q

Describe the therapeutic range of warfarin

A

Narrow

16
Q

List the CI of warfarin

A

Peptic ulcer, severe HTN, pregnancy, bleeding disorders

17
Q

How is warfarin taken?

A

PO OD

18
Q

What is warfarin used for?

A

Long term anticoagulation

19
Q

When should warfarin be used with caution?

A

Elderly and those with past GI bleeds

20
Q

Give the doses and colours of warfarin tablets

A
White = 0.5mg
Brown = 1mg
Blue = 3mg
Pink = 5mg
21
Q

Name some drugs which increase activity of warfarin

A
Alcohol
Allopurinol
Amiodarone
Levothyroxine 
Phenytoin 
Aspirin 
Chloramphenicol 
Simvastatin 
Ciprofloxacin
Erythromycin
22
Q

Name some drugs which decrease the activity of warfarin

A
Barbiturates
Vitamin K 
Carbamazepine 
Rifampicin 
Steroids
23
Q

Name some direct oral anticoagulants

A

Rivaroxaban
Apixaban
Dabigatran

24
Q

Give the mechanism of action for dabigatran

A

Direct thrombin inhibitor (II)

25
Q

Give the mechanism of action for rivaroxaban and apixaban

A

Factor Xa inhibitors

26
Q

Do DOACs require any monitoring?

A

No - just quarterly assessment and annual blood test

27
Q

List the CI to DOACs

A

Active bleeding
Lesion at risk of bleeding
Decreased clotting factors

28
Q

Which two drugs interact with DOACs

A

Heparin

Clopidogrel

29
Q

Give the mechanism of action of fondaparinux

A

Penta saccharide Xa inhibitor

30
Q

When may fondaparinux be used?

A

ACS or in place of LMWH for prophylaxis

31
Q

Describe how you switch between LMW/UFH to warfarin

A

Give heparin in combination and continue until INR is in therapeutic range for 2 consecutive days
Start warfarin 5-10mg on days 1 and 2 at 18.00, then check INR on day 3 (takes 48-72hrs to work)
Adjust dose according to INR
Measure INR in alternate days till stable, then weekly, then less often

32
Q

Describe how you transition from heparin to a DOAC

A

Do not administer heparin with a DOAC

Just switch

33
Q

Describe how you manage a UFH overdose?

A

Stop infusion

34
Q

What should you give someone with an UFH overdose who is bleeding

A

Protamine sulphate

35
Q

Name two things which can be used to reverse warfarin

A
Vitamin K (but takes ages to work)
Prothrombin complex concentrate
36
Q

What is contained in a prothrombin complex concentrate

A

Factors 2,7,9,10

37
Q

Give the targeted INRs

A

2-3 if DVT/PE
3.5 if recurrent or while anticoagulated
2-3 if AF
2-3.5 if prosthetic metal valve

38
Q

How long should someone be anticoagulated for after 1st episode of VTE

A

3 months or 6 months if life threatening clot at presentation and those with transient but persistent RF

39
Q

How long should a person be anticoagulated for if recurrent unprovoked emboli or underlying thrombophilia?

A

Indefinite treatment but consider bleeding risk

40
Q

How long before surgery should warfarin be stopped?

A

5 days

41
Q

How does warfarin affect PT and APTT?

A

Increased PT

Normal APTT

42
Q

At what INR should warfarin be restarted after being stopped due to bleeding?

A

<5