Anticoagulant, anti platelet, and thrombolytic drugs Flashcards
What is hemostasis?
bleeding is stopped
What does hemostasis do?
maintain steady blood flow
What are the components of hemostasis
platelets, blood proteins, endothelial cells, sub endothelial matrix
what is the initial response when a blood vessel is damaged
vasoconstriction or vascular spasm
what are the three steps of hemostasis (blood clotting)
vasoconstriction/spasm, platelet clot, coagulation
What breaks down the clot eventually
plasmin
what is the normal platelet count
150,000-400,000
what platelet count does abnormal bleeding in response to trauma occur
below 100,000
what platelet count does spontaneous bleeding episode occur
below 20,000: stop giving blood thinner
What controls platelet activation
endothelial cells lining blood vessels
What is the role of platelet activation (3)
regulation of blood flow, platelet to platelet interaction, clotting cascade activation
what happens during regulation of blood flow to damaged site
vasoconstriction/spasms
what happens during platelet to platelet interaction
platelet plug: stops further bleeding
what happens in activation of clotting cascade
stabilizes plug, initiates repair process
What happens during coagulation cascade
release of clotting factors: temporary plug,
chemical reactions: thrombin formation
fibrin traps blood cells: clot forms
How is inactivation of clotting factors accomplished
anti-thrombin
what is antithrombin?
does not clot
How is the clot removed once vessel is healed?
plasmin degrades: produced through plasminogen
What is used in the lysis of blood clots (3)
d-dimer, fibrin degradation, plasminogen +plasmin
why do you want to check d-dimer
lab levels will be high: can indicate if there is a blood clot
What is thrombophlebitis?
development of thrombus in vein INFLAMMATION present
What is phlebothrombosis?
thrombus in vein with NO inflammation; asymptomatic
What are factors for thrombus development? (3)
immobile pt. (slow blood flow), endothelial injury, increased blood coagulability (genetic, dehydration, pregnant)
What are the S+S of thrombophlebitis and phlebothrombosis?
often unnoticed, ache, burn, tender (DVT), fever, malaise, leukocytosis
What is a complication of thrombophlebitis and phlebothrombosis?
pulmonary embolism
What is the treatment of thrombophlebitis and phlebothrombosis?
excercise, elevate, compression hose, SCD, surgery
Who is at high risk of blood clots
elderly and hospital pt. b/c they are immobile
What is an embolus?
the clot breaks off and travels to heart, brain, lungs
What are embolism S+S to lungs and heart
chest pain, SOB, decrease O2, increased RR + BP, tachycardia
What are the 3 major drug groups for thromboembolic disorders?
anticoagulants, antiplatelets, and thrombolytics
What do anticoagulants do?
reduce formation, inhibit synthesis and activity of clotting factors
What do anti platelets do?
suppress platelet aggregation
What do thrombolytics do?
remove already formed clots
What are the two anticoagulants
heparin: unfractioned and low-molecular-weight heparin
What are anticoagulants used for
prevention of venous clots, reduced thrombin, suppress clot
What is heparin unfractioned
rapid-acting, immediate response
How is heparin unfractioned given
IV or subQ NO PO
What are the adverse effects of heparin unfractioned
hemorrhage, heparin-induced thrombocytopenia
What are the contraindications of heparin unfractioned?
uncontrolled bleeding, during/after surgery of eye, brain, spinal cord
How do you evaluate effectiveness of heparin unfractioned
aPTT normal: 30-40 seconds
What is the antidote for heparin
protamine sulfate
What are advantages of low-molecular-weight heparin
longer half-life, doesn’t require monitoring, given SubQ, costs more
example of low-molecular- weight heparin
enoxaprin
What is low-molecular-weight heparin used for
prevent DVT after knee surgery, established DVT, ischemic complications
Adverse effects of low-molecular-weight heparin
neurologic injury with spine
What is warfarin
oral anticoagulant with delayed onset, doesn’t affect clots already formed
When is warfarin used
long-term, never in emergencies PREVENTION
How long does warfarin remain in bloodstream after last dose
2-5 days
How do you monitor warfarin
international normalized ratio (INR) normal:<1 abnormal: 2-3
adverse effects of warfarin
fetal hemorrhage
what are the interactions of warfarin
heparin (increases), aspirin (promotes bleeding), oral contraceptives and vitamin K (decrease)
Antidote for warfarin
vitamin k: IV or food
what are some vitamin k foods
leafy greens, mayo, oil
What do the direct thrombin inhibitors do
directly inhibit thrombin, don’t take with food
what do the direct factor Xa inhibitors do
inhibits thrombin production
What are anti platelet drugs used for
suppress aggregation, decrease clot formation
What does aspirin do
prevents clots
adverse effects of aspirin
increases GI bleed risk
what has a similar adverse effect to aspirin
clopidogrel: stents
How do you minimize bleeding risk
reduce moving pt, poking them, invasive procedures, concurrent anticoagulants and anti platelet drug
