Chapter 13 lecture notes Flashcards
What is hemostasis?
Blood’s ability to form a clot to stop bleeding from the arteries and veins of the body.
What type of drugs prevent clot formation?
Antiplatelet drugs and Anticoagulants
What drugs dissolve a clot that is already formed?
Thrombolytics
When bleeding occurs in the body, three mechanisms reduce blood loss, what are they?
- Vascular spasm
- Formation of a platelet plug (Platelet Inhibitors work here)
- Blood clotting (coagulation) (anticoagulants work here)
Vascular spasm
When blood vessel is severed, it snaps back (retracts), smooth muscle contracts and the lumen becomes smaller resulting in less blood loss - drugs are not apart of this mechanism of clotting.
Platelet plug
2nd step in hemostasis occurs when platelets become activated & begin to get sticky & adhere to the inner walls of damaged blood vessels to form a platelet plug.
Coagulation
Blood Clotting -blood congeals to form a clot around the platelet plug. -Made possible by: >presence of clotting proteins >occurs in a cascade
What does cascade mean in coagulation?
as one clotting protein becomes activated and triggers the next protein, and the next, and the next, and so on…
Fibrinolysis
Fibrinolytic system comes into play after the damaged blood vessel is repaired & the body works to dissolve the blood clots that are no longer needed.
What is plasminogen?
substance in blood activate plasminogen to become plasmin which is the enzyme that dissolves clots
TPA
Tissue Plasminogen Activators
Drugs that dissolve clots
“Clot busters”
Clotting in an unbroken artery or vein is called??
Thrombus and the abnormal disease process that accounts for it is called Thrombosis.
Abnormal thrombi are usually initiated by…
roughened, diseased surface of a blood vessel. Can occur from atherosclerosis, trauma, or infection.
Stasis blood flow means??
When blood flow slows down, can also cause blood clots.
What 4 factors help keep blood flowing normally??
Undamaged blood vessels
smooth surfaces
good circulation
non-sticky platelets
Embolus
Is a piece of the atherosclerotic thrombus, blood clot, air bubble, or piece of fat or other debris that is transported by the bloodstream.
Drug therapy in this chapter is aimed ate preventing…
- platelet activation on top of unstable thrombi.
2. and so they cannot break away and obstruct blood flow at sites far from their formation.
What are the 3 different types of anti-clotting drugs?
- Platelet Inhibitors
- Anticoagulants
- Thrombolytics
Platelet Inhibitors
hinder the ability of platelets to get sticky and form a platelet plug.
Anticoagulants
Of the “deep clotting cascade” hinders one or more steps in the cascade of soluble clotting factors that lead to formation of thrombin.
Thrombolytics
“clot busters” drugs that dissolve clots after it has already formed.
Antiplatelet drugs are used to:
- Prevent or treat superficial venous thrombosis, mild cases of DVT
- Prevent “mini strokes” called TIAs
- Prevent and treat angina
- make platelets less sticky
What are the different platelet inhibitor drugs?
Aspirin/NSAIDS - relieve angina & prevent heart attacks & stroke.
Plavix/Clopidogrel - 2nd best selling drug world wide,
Any bleeding seen from platelet inhibitors is called?
“Superficial bleeding”
Coumadin
anticoagulants adverse effects which include bleeding into the joints, abdomen, or brain
Superficial bleeding complicates administration of _____ ___ ______ ______ being administered.
aspirin-like platelet inhibitors
Anticoagulants are powerful drugs used to:
- Provide anticoagulation during hemodialysis & cardiopulmonary by pass (CPB)
- Prevent or treat DVT or pulmonary embolism (PE)
- prevent or treat stroke & recurrence
- prevent or treat MI & recurrence
How do Anticoagulants work??
work by interrupting one or more of the coagulating cascades (clotting steps)
Heparins
Mostly used in the hospital,only use them for a few days,Administered by IV (olden days)
Affect the intrinsic pathway of the cascade
Coumadin
Affect the Extrinsic Pathway of the cascade
Lovenox
Heparin that is given to out patients
Clot busters are not…
Anticoagulants
We only give thrombolytics for…
stroke and heart attack
