Anti coag drugs

Question 1

indications of anticoagulant drugs

Answer 1

venous thrombosis

atrial fibrillation

Question 2

what do anti coagulants target

Answer 2

formation of the fibrin clot

Question 3

heparin

warfarin

Answer 3

ATTP

PT

Question 4

heparin potentiates what
effect
how is it given
forms

Answer 4

potentiates antithrombin
immediate effect
parenteral - IV or SC
2 forms - unfractionated IV, low molecular weight (LMWH) - SC

Question 5

why can AFib lead to a stroke

Answer 5

Stasis in the left atrium – fibrin clot can be formed on the wall – blood clot can break off and go straight up the caroti artery into the brain and can lead to a very severe stroke

Question 6

other indications for anti coag

Answer 6

valve replacements - metal valves

Question 7

heparin stops what

Answer 7

breaking apart of the thrombin/factor 10 and antithrombin complex

Question 8

how do the two types of heparin work and which is monitored more

Answer 8

LMWH – antthrombin and factor 10 – needs less monitering

Unfractionated – antithrombin and thrombin

Question 9

monitoring of heparin

Answer 9

APTT for unfractionated

anti 10 assay for LMWH but not really monitored as more predictable response

Question 10

when is LMWH monitered

Answer 10

kidney disease
obesity
pregnancy

Question 11

why APTT for heparin

Answer 11

more sensitive than PT

Question 12

heparin complications

Answer 12

bleeding
heparin induced thrombocytopenia (with thrombosis) - HITT - monster FBC in patients on heparin
osteoporosis with long term - higher risk with unfractionated

Question 13

heparin reversal

Answer 13

stop the heparin - short half life

in severe bleeding - protamine sulphate, reverses antithrombin effect
complete reversal for unfractionated
partial reversal for LMWH

Question 14

coumarin anticoag

mechanism of action

Answer 14

warfarin, phenindione, acenocoumarin, phenprocoumon

inhibition of vit K

Question 15

vit K is what
where is it absorbed
requires what for absorption
final carboxylation of what

Answer 15

fat soluble vitamin
upper intestine
requires bile salts
of clotting factors 2, 7, 9, 10

Question 16

what proteins w bit K

where synthesised

Answer 16

protein C and protein S

synthesised in liver

Question 17

vit K and platelets pos and neg what

Answer 17

vit k makes the factors neg

and the platelets release calcium which is pos

Question 18

warfarin initiatiation
window
maintanence
metabolised where

Answer 18

rapid and slow

narrow therapeutic window

maintanence - dose should be taken at the same time every day

stabilise them

metabolised in the liver w cytochrome p450

Question 19

what should the INR be between

Answer 19

1-3

Question 20

warfarin prolongs what

Answer 20

PT - better test

APTT is also prolonged

Question 21

what is the INR

Answer 21

patients PT time (sec) / mean normal PT time in seconds all to the power of ISI

Question 22

major risk factor with warfarin

Answer 22

haemorrhage

Question 23

factors that influence bleeding risk w warfarin

Answer 23

intensity of anti coag 
concomitant clinical disorders
concomitant use to of other medications 
drug interactions 
quality of management

Question 24

bleeding complications

Answer 24

mild - skin bruising, epistaxis, haematuria

severe - GI, intracerebarl, drop in HB

Question 25

warfarin reversal

Answer 25

no action
omit warfarin dose(s) - takes a few days for warfarin to come down
oral Vit K - 6 hours
clotting factors (FFP or factor concentrates 2 7 9 and 10) - immediately warfarin comes down
clinical and lab assessment of response

Question 26

type of new anticoagulants

Answer 26

oral direct thrombin inhibitors - dabigatran PO

oral factor 10 inhibitors - riveroxaban, apixaban

Question 27

con of new anticoag

Answer 27

no specific antidote – have been developed

Question 28

who are new anti coag drugs used in

Answer 28

instead of LMWH as prophylaxis in elective hip and knee replacement surgery
stroke prevention in AFIb in some px
treatment for DVT/PE