anticoagulation therapeutics Flashcards
major steps in haemostasis
vascular spasm
formation of platelet plug - platelet adhesion to damaged collagen
conversion to a clot by reinforcement with fibrin
tissue repair
ADP
serotonin
TxA2
sticky platelets
vasoconstrictor
vasoC and activates
why doesn’t the platelet plug spread along the vessel
prostacyclin - from intact endothelium inhibits platelet adhesion and aggregation
NO - from intact endothelium inhibits platelet adhesion
liver role in clotting
bile salts in bile cause gi tract to absorb vitK
fibrinolytic
fibrinolytic drug, also called thrombolytic drug, any agent that is capable of stimulating the dissolution of a blood clot (thrombus). Fibrinolytic drugs work by activating the so-called fibrinolytic pathway.
clot busters
Eminase (anistreplase)
Retavase (reteplase)
Streptase (streptokinase, kabikinase)
t-PA (class of drugs that includes Activase)
Background. Heavy menstrual bleeding (HMB) is an important physical and social problem for women. Oral treatment for HMB includes antifibrinolytic drugs which are designed to reduce bleeding how
which are designed to reduce bleeding by inhibiting clot‐dissolving enzymes in the endometrium.
what is an anticoagulant
Drug that interrupts the process involved in the formation of blood clots
called blood thinner
anticoagulants are different to antiplatelet medicines, such as aspirin and clopidogrel.
because They act on components of the clotting cascade!
how do antiplatlets work
reduce the ability of the platelets to stick together and reduces the risk of clots forming
4 ways we can quantify clotting capability
measure platlets
calculate INR ( standardised)
measure prothrombin time
measure ATPR
Platelet count = maximal strength of clot and time to stop bleeding reflected by this
prothrombin time
time to initiate coagulation (evaluates intrinsic pathway)
ATPR
measures effectiveness of reinforcing the clot (evaluates contact pathway)
what is the INR
what should your value be if taking a blood thinner
INR = Ratio of patient’s Prothrombin time to the normal population
between 2-3
prothrombin is made where
liver
precusor for thrombin
do warfarin and heparin need measuring with blood tests
yes
4 types of DOACs
rivaroxaban (Xarelto)
dabigatran (Pradaxa)
apixaban (Eliquis)
edoxaban (Lixiana)
which anticoagulant is a pentasaccharide
how does heparin work - what factors and what does it activate
heparin - encourages body natural clot lysis to break down clots that have formed acting of 10a and 2a preventing fibrin clot formation by activating antithrombin h=which is the bodys natural anticlht protein
heparin essentially brings antithrombin and factor 10 close together to speed up the reaction
difference between unfractioned and LMWH
LMWH enoxaparin binds less avidly to plasma proteins and therefore has increased bioavailability and duration of action - lower risk of osteoporosis and lower risk of HIT