Anti-coagulant medication Flashcards
What are the three different types of anti-coagulant medications?
Vitamin K antagonists
Direct Oral Anti-Coagulants (DOACs)
Low molecular weight heparins
What are the 5 oral anti coags licensed for use in the UK?
Rivaroxaban
Apixaban
Warfarin
Edoxaban
Dabigatran
What happens immediately after damage to the smooth muscle in blood vessel walls?
Vasoconstriction response makes the hole smaller and reduces blood loss
How do platelet plugs form?
When collagen fibres are damaged they signal and activate megakaryocytes (platelets). When the platelets see the damaged exposed collagen they stick to it forming a negatively charged plug
Where are platelets produced?
Bone marrow
How is thrombin formed?
Platelets start to stick together and release prothrombin activator which activates prothrombin.
When prothrombin activator and active prothrombin combine they form thrombin.
Where is prothrombin produced?
In the liver
What does thrombin do?
It breaks down fibrinogen into fibrin which will collect at the site of the platelet plug beginning coagulation
What is the most commonly prescribed anti-coag?
Warfarin
How does warfarin work?
Inhibiting vitamin K synthesis in the intestine, slowing the production of prothrombin. It also works to inhibits factors VII, IX & X.
Why do newborn babies receive vitamin K injections?
They do not have enough bacteria in the gut at birth to produce vitamin K. The injection protects them from uncontrolled haemorrhage
Why do patients taking warfarin have to get regular blood tests?
They require INR (International Normalised Ratio) tests, usually every 4-5 weeks, which is calculated using the time it takes for your blood to clot
What is target INR?
2.5 for patients on warfarin, 1 for patients not on warfarin
How do each of the 5 DOACs licensed in the UK work?
Apixaban, edoxaban and rivaroxaban all prevent factor X from becoming active
Dabigatran stops prothrobin (factor II) from being activated
Warfirin inhibits formation of vitamin K dependant clotting factors
What is fragmin?
The trade name for dal-teparin, a drug that is part of the family of heparin based drugs. Fast acting with a short half life. It is sometimes used in the community for injection at home
