Anticoagulant drugs

Question 1

thrombotic events- arterial

Answer 1

coronary, cerebral, peripheral= antiplatlet drugs

Question 2

thrombotic events- venous

Answer 2

dvt, pe= anticoagulant drugs

Question 3

indications anticoagulant drugs (2)

Answer 3

venous thrombosis

atrial fibrillation- 85%

Question 4

anticoagulant drug targets

Answer 4

formation of fibrin clot

Question 5

venous thrombosis (3)

Answer 5

low pressure system

platlets not activated

activates coagulation cascade - rich in fibrin clot

Question 6

naturally occurring anticoagulants

Answer 6

1. serine protease inhibitors
   antithrombin natural defence
   - thrombin key to haemostasis =fibrinogen to fibrin
2. protein c + s= switch off clotting factors 5 + 8 - reduces chance thrombosis

Question 7

heparin (3)

Answer 7

potentiates antithrombin

immediate effect

2 forms= unfractionated + LWMH

Question 8

Unfractionated

Answer 8

prolongs aptt prothrombin time

Question 9

LWMH

Answer 9

antithrombin bind to thrombin or activated factor 10 and that complex switch sit off, heparin wraps round it

Question 10

heparin monitoring (2)

Answer 10

unfractionated- Activated partial thromboplastin time (APTT)

LWMH- Anti-Xa assay but usually no monitoring required- unless renal failure

Question 11

heparin complications (3)

Answer 11

bleeding​

heparin induced thrombocytopenia (with thrombosis) HITT - monitor FBC in patients on heparin​

osteoporosis with long term use​

Question 12

heparin reversal (5)

Answer 12

stop the heparin (short t1/2)​
​
in severe bleeding -​
=protamine sulphate​
=reverses antithrombin effect​
=complete reversal for unfractionated​
=partial reversal for LMWH​

Question 13

coumarin anticoagulants - mech of action

Answer 13

inhibition of vitamin K

Question 14

coumarin anticoagulants - drugs (4)

Answer 14

warfarin​!

phenindione​

acenocoumarin​

phenprocoumon​

Question 15

vitamin K (4)

Answer 15

fat soluble vitamin​

absorbed upper intestine​

requires bile salts for absorption​

final carboxylation of clotting factors II, VII, IX and X​

Question 16

vit K dependent factors (3)

Answer 16

factors II (prothrombin), VII, IX & X​
=protein C and protein S​

synthesised in liver​

require vitamin K for final carboxylation step essential for function​
​

Question 17

warfarin- mech of action

Question 18

warfarin therapy (4)

Answer 18

initiation​=
-rapid​
-slow​

stabilisation​

maintenance​
=dose should be taken at same time every day (6pm recommended)​

narrow therapeutic window - need to monitor therapy
​

Question 19

warfarin monitoring

Answer 19

INR
(INR = PTRISI​)

Question 20

warfarin: major adverse effect - haemorrhage (6)

Answer 20

factors that may influence bleeding risk:=
-intensity of anticoagulation​
-concomitant clinical disorders​
-concomitant use of other medications ​
-BEWARE DRUG INTERACTIONS​
-quality of management​

Question 21

INR

Answer 21

Patient’s PT in Seconds​ /
Mean Normal PT in Seconds​

Question 22

bleeding complications from warfarin (6)

Answer 22

mild=
-skin bruising, epistaxis, haematuria

severe=
-gastro, intracerebral, drop in Hb

Question 23

warfarin reversal (5)

Answer 23

1. no action
2. omit warfarin dose(s)
3. administer oral vit K
4. administer clotting factors
5. ​clinical + lab assessment of response​

Question 24

management of bleeding (6)

Answer 24

dependant on= sev of bleeding​ + INR​
​
speed of action=
vitamin K - 6 hours​
clotting factors - immediate​

Question 25

new anticoagulants- direct activated factor X inhibitors (3)

Answer 25

-apixaban -edoxaban -rivaroxaban

Question 26

new anticoagulants- direct thrombin inhibitors

Answer 26

dabigatran

Question 27

new anticoagulants- benefits (3)

Answer 27

Oral and no monitoring required​ Less drug interactions​ Recently developed specific antidotes for reversal​

Question 28

new anticoagulants- when used ? (3)

Answer 28

initially used instead of LMWH as prophylaxis in elective hip and knee replacement surgery​ used for treatment of DVT/PE​ introduced for stroke prevention in atrial fibrillation for new patients​ ​