Pharmacology: Haemostasis Flashcards
haemostasis
arrest of blood loss from a damaged vessels
stages in haemostasis
- vascular damage exposes collagen and TF
- vasoconstriction, platelet adhesion and aggregation by fibrinogen
- formation of clot by TXA2 and ADP with P2Y12
what are anticoagulants used in?
venous thrombosis and embolism (DVT, post-op, artificial heart valves and AF)
what do all anticoagulants carry a risk of?
haemorrhage
mechanism of action of warfarin
renders factors II, VII, IX and X inactive
how is an overdose of warfarin treated with?
phytomenadione
factors that increase warfarin action
- liver disease
- metabolic rate
- NSAIDS
factors that lessen the action of warfarin
- pregnancy
- vitamin K consumption
mechanism of action of heparin
binds to antithrombin III which inhibits Xa and IIa
examples of LWMHs
enoxaparin
dalteparin
mechanism of action of LMWHs
inhibits Xa not IIa
adverse of heparin and LMWHs
osteoporosis
hypoaldosteronism
hypersensitivity
orally active inhibitors
dabigatran etexilate
rivaroxaban
when are antiplatelets used
arterial thrombosis
four types of anticoagulation
- warfarin
- heparin
- LMWHs
- orally active inhibitors
three types of antiplatelets
- asprin
- clopidogrel
- tirofiban
mechanism of action of aspirin
blocks COX in platelets
adverse of aspirin
GI bleeding and ulceration
mechanism of action of clopidogrel
links to P2Y12 receptors
when is clopidogrel used
if intolerance to aspirin
when is tirofiban used
prevent MI for patients with stable angina
what are fibrinolytics used used for?
reopen arteries following MI and stroke
two types of fibrinolytics
- streptokinase
2. alteplase and duteplase
what is streptokinase
protein extracted from streptococci (action blocked after 4 days due to generation of antibodies)
adverse of streptokinase
can cause allergic reaction
what are alteplase and duteplase
recombinant tissue plasminogen activator
two types of diuretics
- thiazide
- loop
example of a thiazide diuretic
bendoflumethiazide
example of a loop diuretic
furosemide
adverse of diuretics
diabetes exacerbation gout exacerbation hyperaldosteronism hypokalaemia enlarged prostate (urinary retention)
what is fondaparinux?
anticoagulant Xa inhibitor
which drug is the anticoagulant of choice for mechanical valves?
warfarin
