Anti-coagulant reduce coagulation in blood vessels. The drugs given to us to learn are:
- UF Heparin (iv)
- Low molecular weight heparin: Enoxaparin s.c. (Clexane)
- VKAs: Warfarin (oral)
- DOACS: Dabigatran Etexilate, Rivaroxaban.
It is helpful to refresh on the coagulation cascade
Heparins and LMWH.
(Unfractionated) Heparin is molecule in the body reduces fibrin formation via increasing the action of antithrombin binding to prothrombin (Xa) and thrombin (IIa).
There is the danger of haemorrhage but it can be reversed.
LMWHs are modified and increasing binding to factor Xa but not IIa. It can be delivered subcutanously.
The 2 main drugs are:
Vitamin K antagonists
The name is originally german (Vitamin Koagulation). Vitamin K is needed for the post translational activation of factors X, IX, VII, II (1972). Vitamin K is present in the diet and a number of vitamin replacement products. So ask patient about supplements
Warfarin stops vitamin k from being regenerated to be used for coagulation factor production.
Dabigatran is not good with valvular disease or prosthetic valves which is why warfarin is still used
DOACs
These are direct thrombin inhibitors
The 2 main DOACs we cover are: