anti-platelete and anti-coagulant therapy

Question 1

what is the mechanism of heparin ?

Answer 1

heparin stimulates antithrombin 3 which in turn inactivates factor Xa and factor IIa

Question 2

how is heparin monitored ?

Answer 2

1- unfractionated heparin - aPTT
2- anti-Xa assay for low molecular weight heparin
when a patient iis not taking heparin it should be zero

Question 3

what is the normal PT ?

Answer 3

10-13 seconds

Question 4

what is the normal PTT ?

Answer 4

25 to 35 seconds

Question 5

what is the advantage of LMWH overr unfracctionated?

Answer 5

longer half life
less cchane of bleeding
dosing is simple
no need to monitor

Question 6

what are the indications of unfractionated heparin ?

Answer 6

1- if the risk of bleeding is high
2- in situations where rapid reversal of anticoagulation is necessary is required
3- in massive PE following thrombolysis
4- in cases of proximal LL oedema where LMWH is not working

Question 7

is unfractionated heparin or LMWH easier to reverse ?

Answer 7

unfractionated heparin
both reversed by protamine sulphate

Question 8

what is the treatment of overdose of heparin ?

Answer 8

in unfractionated heparin , stop the infusion which is usually sufficient if not then give protamine sulphate

Question 9

why is warfarin bridged by heparin ?

Answer 9

because warfarin reaches its maximum effect after 3-5 days
also warfarin inhibits protein C and S at the beginning ( inhibits anticoagulation)

Question 10

which anticoagulant is safe for pregnancy ?

Answer 10

heparin not warfarin

Question 11

what is the mechanism of action of warfarin ?

Answer 11

inhibits vitamin k which in turn inhibits the activation of the coagulation factors

Question 12

which pathway does warfarin inhibit ?

Answer 12

extrinsic pathway

Question 13

what is the clinical use of warfarin ?

Answer 13

for purposes of chronic anticoagulation

Question 14

how is warfarin monitored ?

Answer 14

using INR ( prolongs PT )

Question 15

what is the target INR for patients on warfarin ?

Answer 15

for DVT or PE target is 2.5 (between 2-3)
patients with recurrent VTE the target is 3.5 ( 3-4)

Question 16

what are the complications of warfarin ?

Answer 16

bleeding
fatal bleeding
purple toes syndrome

Question 17

what are the drugs that interact with warfarin ?

Answer 17

antifungals
amiodarone
aspirin containing products

Question 18

when do we consider that the patient is in warfarin toxicity ?

Answer 18

INR above 5

Question 19

what is the treatment of warfarin overdose ?

Answer 19

1- INR 6-8 but no bleeding , or minor bleeding - stop the warfarin for 24-48 hours , reccheck INR and then re introduce the drug art a lower dose in 2-7 days

2- INR more than 8 with no bleeding or minimal bleeding , then stop the warfarin for 48 hours , consider oral vitamin K or slow infusion of vitamin K

3- life threatening or sight threatening
stop warfarin
administer prothrombin complex concentrate
also give vitamin K to maintain reversal

Question 20

why is fresh frozen plasma not recommended for warfarin toxicity ?

Answer 20

not fast enough

Question 21

what are the absloute contraindications to anticoagulants ?

Answer 21

haemorrhagic diathesis
severe hypertension
previous cerebral hge
CNS trauma
GI bleeding
history of heparin sens or HIT

Question 22

what are the relative contraindications to anticoagulants ?

Answer 22

uremia
liver disease
chronic alcoholism
subacute bacterial endocarditis

Question 23

when is thrombolysis used ?

Answer 23

Massive PE
phlegmasia cerulea dolens

Question 24

when is an IVC filter used instead of anticoag in PE ?

Answer 24

1- when anticoagulants are absolutely contraindicated
2- recurrent VTE despite therapy
3- serious complications due to anticoag
4- free floating thrombus
5- patients with limited pulmonary reserve won’t survive another PE

Question 25

what are the new oral anticoagulants ?

Answer 25

direct thrombin inhibitors
factor Xa inhibitors

Question 26

what are examples of anti platelets ?

Answer 26

aspirin , clopidogrel

Question 27

when can dabigatran be used ( direct thrombin inhibitor ) ?

Answer 27

1- primary prevention of VTE in patients undergoing total hip replacement
2- prevention of stroke and systemic embolism in patients with nonvalvular Afib
3- treatment and prevention of DVT and PE in adults

Question 28

what are the uses of rivaroxaban ( factor Xa inhibitors ) ?

Answer 28

1- prevention of VTE in adult patients undergoing hip or knee replacement
2- prevention of stroke and systemic embolism in non valvular afib
3- treatment of DVT and prevention of recurrent DVT and PE in adults

Question 29

what is the first line treatment for ACS ?

Answer 29

percutaneous coronary intervention
aspirin
if not aspirin then clopidogrel

Question 30

if the problem is central or peripheral ?

Answer 30

clopidogrel