Anticoagulants and Antiplatelets Flashcards
what is hemostasis?
the stopping of blood flow
what are the three steps of hemostasis?
- vasoconstriction
- platelet plug
- clotting cascade
when does vasoconstriction happen?
after endothelial injury
what does vasoconstriction consist of?
reduced blood flow and surfaces press together
what triggers a platelet plug?
collagen exposure
collagen is adhesive and platelets aggregate on it
what does a platelet plug consist of?
ACTIVATED platelets (w/ “legs” aggregate to form a plug)
activated platelets secrete stimulators triggering the clotting cascade
what happens during a clotting cascade?
activated platelets change in shape, aggregate and secrete stimulators ADP and Thromboxane A2 (TXA2) which causes more aggregation and stabilizes the clot
what is a clotting cascade triggered by?
intrinsic pathway: collagen exposure
extrinsic pathway: tissue factor= thromboplastin released from injured tissue
what are the antiplatelet medications?
aspirin (salicylate)
clopidogrel
what are the anti-coagulant medications?
rivaroxaban (xarelto)
apixaban (Eliquis)
warfarin (coumarin)
what does acetylsalicylic acid (ASA) do?
prevents platelet aggregation
prevents the formation of TXA2
what is the indication for Acetylsalicylic acid?
stroke and MI prophylaxis, high cholesterol (prevent clots on narrowed/vasoconstricted vein/arteries)
what are the adverse effects of aspirin?
GI bleeding, dyspepsia
can take enteric coated to help prevent stomach ulcer damage (1/2 life is longer)
what is dyspepsia?
heart burn
what are the drug-drug interactions to be concerned with for aspirin?
increased risk of bleeding with anti-coagulant and anti-platelet medications
why would a pt. receive both acetylsalicylic acid and clopidogrel?
it has been shown to be effective in pt. with cardiovascular conditions and stroke
what does -penia mean?
lack of
what is clopidogrel?
an ADP inhibitor
alters platelet membrane and prevents signal to aggregate
what does ADP stand for?
adenosine diphosphate
what is clopidogrel commonly paired with?
aspirin
what are the indications for clopidogrel?
prophylaxis of stroke, TIA, MI, and post MI
what is TIA?
transient ischemic attack
mini strokes
what are the adverse effects of clopidogrel?
bleeding
what is clopidogrel bound to?
94-98% bound to protein (albumin) for 5 days
what health problems can cause a low platelet count?
cancers, and hereditary disorders
platelet count lab test info
part of a CBC
normal range:
150,000-400,000 platelets per mcL
<150,000 = thrombocytopenia
<80,000 anti-platelet therapy discontinue
what are the anti-platelet nursing implications?
avoid IM injections
discontinue 5-7 days before surgical procedures
abrupt discontinuation may ↑ risk of CV events
assess CBC (H/H, platelet count)
what is the patient teaching info for anti-platelet medication?
use soft, electric toothbrush,
prevent injury
report for signs of bleeding
food-herbal interactions cause ↑risk of bleeding
what are food-herbal interactions for antiplatelet medications?
chamomile
feverfew
garlic
ginger
gingko
the two pathways of the clotting cascade have a ______________ pathway
shared final pathway
prothrombin → thrombin→fibrinogen→ fibrin →fibrin clot
how do rivaroxaban and apixaban prevent coagulation?
has a Xa inhibitor preventing conversion of prothrombin to thrombin and therefore no fibrin mesh can form over clot
what are the indications for rivaroxaban and apixaban?
prophylactic and treatment of clots
used for the ↑ risk or Hx of thrombotic events
what are the adverse effects of rivaroxaban and apixaban?
bleeding
no routine monitoring required
BUT it has a BBW for an ↑ of clots if discontinued abruptly
what are the D-D for rivaroxaban and apixaban?
other anti-coagulants, anti-platelets, aspirin
is there an antidote for rivaroxaban and apixaban?
yes, Andexxa (binds to and negates drug effects)
what is an embolism?
a roaming piece of clot
it breaks off from a large clot and travels and if it gets to smaller vessels it can block the flow
what is an infarction?
blood flow blocked
What is a thrombus?
a blood clot that blocks blood flow, usually in the legs
what are the effects of warfarin?
inhibits four clotting factors that vitamin K depends on
has no effect on a formed clot but prevents clot enlargement
what are the indications for coumarin?
prophylaxis and treatment of thromboembolic events
patients with a fib. are commonly given _________ to help with ________ because of __________
coumarin
blood clots
blood slowing and pooling due to a fib.
warfarin is _______ bound to _________
80%
protein
explain the timing of warfarin’s onset, therapeutic range and return to normal after discontinuation
onset of action is 36-72 hours
3-5 days to reach therapeutic range
normal coagulation returns in 3-4 days
because of the slow onset of action for warfarin what is commonly used?
a “bridge therapy” usually heparin
D-D interactions for warfarin
heparin, NSAIDs, anti-platelet drugs
What are the adverse effects of warfarin?
bleeding
BBW
what is the antidote for warfarin?
vitamin K
how is warfarin monitored?
PT and INR
what is another name for virtamin K
phytonadione
vitamin K information
koagulation vitamin
4 clotting factors
antidote for warfarin overdose
if given warfarin resistance occurs for 7 days
prothrombin time information
measures time it takes for blood clot to form
monitor warfarin
range is 12-15 sec
therapuetic range 1.5-2 times baseline
INR used to interpret PT
International normalized ratio INR
standardized system
normal range 0.8-1.2 (1)
therapeutic range >2-3.5
measured daily in hospital
outpatient lab testing
when taking warfarin vitamin K food must be eaten with _________ and _________
moderation and consistency
what foods are high in vitamin K and decrease warfarin’s effects?
asparagus
broccoli
cabbage
cauliflower
kale
what are the drug-food interactions that increase risk of bleeding with warfarin?
green tea, gingko, garlic, ginger, cranberry juice, chamomile and licorice
what are the nursing implications for anticoagulants?
avoid IM injections (bleeding/hematomas)
assess CBC, PT/INR
observe for s/sx of bleeding
routine time
high-alert med
use of NSAIDs, antiplatelets ↑ bleeding
what is the patient teaching for warfarin?
soft toothbrush/no flossing
electric shaver
assistive devices
report s/sx of bleeding
prevent injury
routine lab tests
herbal/food interactions
