Anticoagulants

learning objectives




·
define anticoagulant

· describe main classes of anticoagulant


M O . .
A for each class


advantages and disadvantages of each class of
anticoagulants

tests used to monitor the anticoagulant effect

give examples of anticoagulant drugs from each class




what are
anticoagulants



·
definition : drugs that prevent/reduce blood clots by inhibiting factors of the coagulation cascade


·
act on the stable clot formation stage in haemostasis


·
more useful for venous thrombus




Anticoagulants and the coagulation cascade




a good target for an anticoagulant in the cascade is factor I o , thrombin




anticoagulant drugs


·
injectable anticoagulant- > Heparin

oral anticoagulant- > Warfarin




Heparin (unfractioned heparin) . A
M O
.




·
Binds and activates antithrombin , enhancing it's activity up to
1000 fold

↓


inhibits factor 11a (thrombin) and factor Xa




Kate y so no fibrin formed


Mrombin no clot

, structure




>
-

naturally in the body




Antithrombin binds to either thrombin
7
or factor 10


↓
stops it from
of Heparin working
binds to
antithrombin
at antithrombin
binding site.




Heparin (unfractionated heparin)




· Administration : intravenous /subcutaneous

·
effective anticoagulant

· main unwanted effect : hemorrhage

↓


* test for CaPTT)
· need for intensive
monitoring monitoring : activated partial thromboplastin time


Close adjusted in function of a PTT)