Anticoagulation therapeutics Flashcards
Time frame for clotting
haemostats seconds - hours
Inflammation hours - days
Proliferation days - weeks
Remodelling weeks - months
How does platelet adhesion occur?
Damage to vessel wall exposes collagen and chemical factors
Platelets adhere using vWF
Platelets are activated and release factors into surrounding area = vasoconstriction and subsequent platelet activation
Prostacyclin inhibits platelet adhesion and aggregation
NO inhibits platelet adhesion
What does ADP do?
Sticky platelets
What does serotonin do?
Vasoconstrictiom
What does thromboxane a2 do?
Vasoconstricts and activates
Fibrinolytics
TPA, streptokinase and urokinase - break down blood clots
Anti-fibrinolytics
Inhibit clot lysis and stabilise clot formation - amicarm, fibrinogen, aprotinin
Anticoagulants
Block clotting cascade to prevent blood from clotting - apixaban, dabigatran, rivaroxaban, warfarin
function of prostacyclin C
Produced by endothelial wall to prevent platelets adhering
How to quantify clotting capability
- Measure platelets
- Calculate INR
- Measure PTT - extrinsic pathway
- Measure APTR - activated partial thromboplastin time - intrinsic
Anti-coagulants
- Warfarin
- DOACs - rivaroxaban, dabigatran, apixaban, endoxaban
- Heparin - acts on 10a and thrombin to prevent coagulation
Heparin indications
DVT PE MI VTE prophylaxis Open heart surgery
Heparin contraindications
Haemorrhage Thrombocytopenia HTN Lumbar puncture Surgery Trauma
Heparin complications
Heparin induced thrombocytopenia
Hyperkalaemia
Hypersensitivity
Warfarin indications
DVT,
PE
AF
Heart valve prosthetics
Warfarin contraindications
Pregnancy Stroke Renal/hepatic disease GI bleed] Hypertension Surgery
Complications of warfarin
Increased bleeding risk
Teratogenic - disordered bone development
Skin necrosis
How does warfarin affect vitamin K?
Prevents vitamin K reductase so there is no reduced vit K = no modification = affects factors 2,7,9,10
What do DOACs inhibit?
Factor 10a/thrombin
Indications for DOAC use
Same as warfarin but not for mechanical heart valve
Contraindications for DOACs
Acute bleeding
Renal insufficiency
Breastfeeding
Hypertension
Complications of DOACs
Dabigatran = GI disturbance Rivaroxaban = constipation
Indications for fibrinolysis
Acute ischemic stroke
PE
MI
Contraindications for fibrinolysis
Aneurysm GI ulcer Surgery Hypertension Endocarditis
Complications of fibrinolysis
Anaphylaxis
Cardiac arrest
Haemorrhage
Hypotension
Antifibrinolytics example
tranexamic acid
Indications for antifibrinolytic use
Menorrhagia
EPistaxis
Prevention and treatment of haemorrhage
Contraindications of tranexamic acid
Convulsions
Haematuria
