Blood Thinners-MJ Flashcards
How do platelets work?
Tissue injury occurs and arachnodinic acid is released causing platelet recruitment and aggregation (TxA2 and ADP). This forms a weak clot. The coagulation cascade is triggered and that creates fibrin that wraps around the clot to make it strong.
What dose of aspirin is needed for anti-platelet effects?
Baby aspirin (81mg)
What does aspirin prevent?
MI and stroke
What is the MOA of aspirin?
Blocks COX1
COX1 converts arachidonic acid to TxA2. When we take aspirin, we block that action, so TxA2 is not created–so no platelet recruitment and aggregation and no coagulation so no fibrin clot–all leads to making you bleed
What are the adverse effects of aspirin?
GI problems (dyspepsia, ulcers, bleeding) Tinnitus (dose dependent)
What kind of antagonist is clopidogrel?
ADP P2Y12
What are the indications for taking clopidogrel?
MI and ischemic stroke
What is the MOA of clopidogrel?
Blocking the production of ADP
ADP is not created, so we don’t get platelet recruitment and aggregation..so no coagulation cascade…so no fibrin clot formed..so you bleed
Clopidogrel is ineffective for __% of people due to _____.
40% of people due to genetic variations
Clopidogrel has many _____ interactions.
CYP
What do we teach our patient to look for to know they are having a GI bleed?
Black, tarry stool (melena)
Coffee ground emesis
What happens if a patient abruptly stops taking clopidogrel?
Can cause clotting to occur too fast–thrombotic event
What is the clotting cascade?
An injury occurs and stuff happens that activates factor X, which activates factor II (thrombin). That works together with fibrinogen to form a fibrin clot
Who gets blood thinners?
DVT and PE (prevention and treatment)
A-fib
MI
Mechanical heart valve
Is warfarin highly variable or highly predictable?
Highly variable
Does warfarin have a low or high therapeutic index?
LOW
What can affect warfarin levels?
Diet (vitamin K) and genetics
What is the MOA of warfarin?
The liver makes clotting factors X and II by using VITAMIN K. After it makes them, vitamin K is deactivated until they are needed to be made again. Warfarin blocks that reactivation of vitamin K. Eventually there is no more clotting factors.
How long does it typically take for there to be no more clotting factors in the body after warfarin deactivates vitamin K?
5 days