Pharmacology and drugs Flashcards
What are the indications for anticoagulation
- venous thrombosis
- arterial fibrilation
What is the target of anticoagulants?
- the fibrin clot
Name naturally occurring anticoagulants
- anti-thrombin
- protein c
- protein s
What is the affect of heparin
- potentiates antithrombin
- works on the natural anti-coagulant defences
What are the 2 heparin types?
- unfractioned (antithrombin)
- LMWH (antithrombin and anti Xa)
How is heparin monitored?
- APPT
- Anti- Xa assay
Heparin complications?
- bleeding
- heparin induced thrombocytopenia (HIT)
How is unfractioned heparin reversed?
- antidote
- protamine sulphate
How does warfarin work?
- inhibition of vitamin k
- May require initial heparin co dosage as intially higher thrombosis risk
- reduces clot fibrin formation
How is warfarin monitored?
- PT
- INR
PT measures the ___ pathway
- extrinsic (TF, VII)
APPT measures?
- intrinsic (XII, IX, VIII, X)
What can reverse warfarin
- vitamin K
- in life threatening = fresh frozen plasma
name a DOAC
- Dabigatran
- renally excreted
How does edoxaban work?
- direct inhibition of factor Xa
- no monitoring required
What is atherosclerosis
- damage to endothelium
- recruitment of foamy macrophages
- plaques rich in cholesterol
What causes stable angina and intermittent claudication
- stable atherosclerotic plaques
- hyalinised and calcified
What causes unstable atherosclerotic plaques?
- plaque rupture
- platelet recruitment
What are risk factors for arterial thrombosis?
- hypertension
- smoking
- high cholesterol
- diabetes mellitus
prevention of arterial thrombosis?
- antiplatelets
- control risk factors
What is platelet adhesion due to?
- damage endothelium
- collagen exposed
- platelets binding to surface glycoproteins and VWF
What causes platelet aggregation
- glycoproteins and fibrinogen
- platelets stick together
What is platelet activation and what causes?
- change of shape of the platelet, to expose phospholipid surface = ca2+
- TXA2, ADP, Thrombin
How does aspirin work?
- inhibits cyclo-oxygenase
- reduced TXA2
- Reduced platelet aggregation
Name some antiplatelet drugs
- aspirin
- clopidogrel
- dipyridamole
Side effects of aspirin?
- bleeding
- inhibit prostoglandins
- gi ulceration
- bronchospas
When is aspirin contraindicated and why?
- asthama
- causes bronchospams
How does clopidogrel work?
- block ADP receptors
- reduced platelet activation
How does dipyridamole work?
- increases cAMP
- reduces platelet activation
