Anticoagulant Flashcards

1
Q

list 2 drug that reduce rivaroxaban level

A
  1. p-gp inducer
  2. CYP3A4 inducer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the pharmacokinetic of the anticoagulant action of oral warfarin

A

onset: 24-72hrs
peak: 5-7 days
duration: 2-5 days (due to the long half life of some of the factor eg II T1/2 50hrs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

where is warfarin metabolise + which enzyme

A

in the liver, primary by CYP2C9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

list 3 a/e of heparin/LMWH

A
  1. bleeding
  2. thrombocytopenia (lesser risk w LMWH)
  3. increase risk of epidural/spinal haematoma & paralysis in pt receiving epidural/spinal anaesthesia or spinal puncture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the pharmacokinetic for dabigatran

A

onset: ~1hr
peak: 3h
duration: 3-5 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

list examples of significant drug-drug interactions with warfarin

A
  1. paracetamol >2 weeks at high dose >2g/day (increase risk of bleeding)
  2. allopurinol, NSAIDS, salicylates, PPI, metronidazole (increase risk of bleeding)
  3. barbiturates, corticosteroids, spironolactone, thiazide diuretic (reduce drug effect)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

list 1 adverse effect of rivaroxaban

A

bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

list example of drug-drug interaction with dabigatran that increase the risk of bleeding

A
  1. antiplatelet
  2. anticoagulants
  3. fibrinolytic
  4. NSAIDS
  5. ketoconazole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the pharmacokinetic of heparin

A

onset: 5-25min
duration: 4hr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

list 1 drug-drug interaction that increase the risk of bleeding with heparin/LMWH

A

SSRI (selective serotonin reuptake inhibitor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the 4 contraindication over the use of heparin/LMWH

A
  1. hypersensitivity to pork product
  2. active bleeding
  3. thrombocytopenia
  4. antiplatelet antibodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

list example of drug-drug interaction with rivaroxaban that increase the risk of bleeding

A
  1. antiplatelets
  2. anticoagulants
  3. NSAIDS
  4. p-gp inhibitor
  5. CYP3A4 inhibitor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

name a reversal agent for rivaroxaban

A

andexanet alfa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

does dabigatran have a short or long bioavailability, what advice should be given to patient

A

short, instruct pt to swallow the medication whole (enteric coated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

a 62 y/o man admitted with DVT is stabilised and restarted on a lower dose of LMWH overlapped with warfarin in preparation of discharge. why is warfarin more appropriate for outpatient therapy

a) warfarin can easily be administered orally
b) warfarin is a safe drug with no drug-drug or drug-food interactions
c) the risk of bleeding with warfarin is less than any other anticoagulant

A

A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

list the 3 adverse effects of warfarin

A
  1. haemorrhage/bleeding
  2. hepatitis (greater risk in >60 y/o, male, warfarin <1 month)
  3. cutaneous necrosis due to reduce blood supply to adipose tissue, typically 3-5 days after treatment initiated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does anticoagulant block in haemostasis (2)

A
  1. block the activation of clotting factor
  2. block the activation of fibrin polymerization
18
Q

list examples of significant drug-food interactions with warfarin

A
  1. traditional herb eg. gingko, ginseng, cranberry juice (increase risk of bleeding)
  2. vitamin k food eg. green tea, leafy green veg (reduce drug effect)
19
Q

list 5 contraindications over the use of warfarin

A
  1. active/risk of bleeding
  2. severe/malignant HTN
  3. severe renal/hepatic disease
  4. subacute bacterial endocarditis, pericarditis, pericardial effusion
  5. pregnancy (teratogen cause severe birth defects in CNS & bones, drug also cause hemorrhagic disorder in fetus)
20
Q

what is the antidote for heparin/LMWH

A

IV protamine sulfate

incomplete reversal of LMWH

21
Q

what class of drugs inhibits secondary haemostasis

A

anticoagulant

22
Q

list 5 caution over the use of warfarin

A
  1. diverticulitis, colitis
  2. mild-mod HTN
  3. mild-mod renal/hepatic disease
  4. breast feeding women
  5. drainage tube in any orifice
23
Q

what is the difference between heparin & LMWH in terms of inactivating clotting factors

A

LMWH are more selective towards factor Xa & to a lesser extend factor IIa

24
Q

a 62 y/o man is admitted to the ED & diagnosed to have DVT in a lower limb, why was he not administered warfarin immediately

a) the risk of bleeding is too great before the patient is stabilised
b) heparins are more potent as they directly inhibit activation of thrombin
c) warfarin is only antiplatelet not anticoagulant
d) the onset of clinical action of warfarin is too slow

A

D

25
Q

list 2 a/e of dabigatran

A
  1. bleeding
  2. GI disturbance eg. dyspepsia, abdominal discomfort
26
Q

what is the pharmacokinetic of LMWH

A

onset: 5-25min
duration: 20hr

27
Q

what is the 3 advantage of LMWH over heparin

A
  1. longer half life
  2. longer bioavailability
  3. lesser risk of thrombocytopenia
28
Q

list examples of drug-food interaction that increase the risk of bleeding with heparin/LMWH

A

gingko, ginseng, ginger, garlic

29
Q

name 4 pharmacological classes of oral anticoagulant drugs

A
  1. vitamin k antagonist
  2. direct oral anticoagulants (DOAC): factor IIa inhibitor
  3. direct oral anticoagulants (DOAC): factor Xa inhibitor
  4. heparin/LMWH
30
Q

what is the drug name of the inactive form of dabigatran

A

dabigatran etexilate

31
Q

what is the pharmacokinetic for rivaroxaban

A

peak: 2.5-4hr
duration: 1-2 days

32
Q

list 3 caution over the use of heparin/LMWH

A
  1. risk of bleeding
  2. elderly
  3. pt w renal insufficiency (for LMWH)
33
Q

a patient is discharged with dual therapy consisting of LMWH overlapping with oral warfarin. what commonly available OTC drug that can increase the risk of bleeding with warfarin must the patient avoid?

a) paracetamol
b) antihistamines
c) aspirin
d) vitamin supplements

A

C

34
Q

name a reversal agent for dabigatran

A

idarucizumab

35
Q

what is the MOA of heparin/LMWH (2)

A
  • it potentiate the action of antithrombin III to inactivate thrombin (IIa)
  • heparin-ATIII complex also inactivate other factors: IXa, Xa, XIa, XIIa
36
Q

name a drug that can be used to reverse the anticoagulation action of warfarin

A

vitamin k

37
Q

what is the 2 route for heparin/LMWH

A

SC/IV

38
Q

list 1 drug that reduce dabigatran level

A

rifampin

39
Q

a 62 y/o man admitted with DVT and administered LWMH develops bleeding. which of the following is the most appropriate cause of action?

a) immediately discontinue LMWH & replace with warfarin
b) immediately discontinue LMWH & administer protamine sulphate
c) continue the LMWH & administer idarucizumab
d) switch to dabigatran

A

B

40
Q

list one drug example of LMWH

A

enoxaparin

41
Q

which coagulation factors does oral warfarin inhibit

A

II, VII, IX, X

42
Q

what is the MOA of warfarin

A

it inhibit the vitamin k reductase enzyme, preventing the reactivation of oxidised vitamin k