Anticoagulants Flashcards
What is the role of Heparin?
potientiates antithrombin - solidifies the bond between anti thrombin and thrombin
LMWH also acts on factor X
What is good about Heparin?
works immediately so is good for acute situations
How is unfractioned Heparin monitored?
APTT
How is LMWH monitored?
no monitoring usually required
if it is - anti Xa assay
What are the complications of Heparin?
Bleeding
Heparin induced thrombocytopenia
osteoporosis in long term use
How can you reverse Heparin?
stop heparin - short half life
in severe cases - protamine sulphate, reverses antithrombin effect (complete reversal of unfractioned, partial of LMWH)
How does Warfarin work?
acts by blocking the ability of Vitamin K to carboxylate factors 10,9,7,2 and protein C and S
How does Warfarin block Vitamin K?
vit K adds on a second COOH group to carboxylate the clotting factors
Warfarin removes this COOH so the chemical bond is too weak for effective attachment of coagulation factors
What are the rules for administering Warfarin?
must be given with heparin for a week to begin with
How is Warfarin action measured?
INR
What is a target INR?
between 2-3
What does a high INR indicate?
too much bleeding
What do you do if you want to decrease the INR i.e. reverse warfarin?
give vitamin K - takes 6 hours to work
What do you give in a major bleed to reverse warfarin?
give clotting factors
What are mild bleeding complications?
skin bruising
epistaxis
haematuria
