8: Coagulation and Hyperlipidemia Flashcards
hemostasis
blood coagulation; normal clotting factors in the blood that are necessary to prevent excessive hemorrhage when blood vessels are damaged
thrombogenesis
thrombus formation caused by overactive clotting, which can lead to vessel occlusion
what types of drugs prevent clot formation?
anticoagulants and antiplatelets
what type of drug removes clots?
fibrinolytics
why is lowering plasma lipid levels important?
this prevents atherosclerosis that can be caused by hyperlipidemia
how does tissue plasminogen activator (tPA) break down a clot?
tPA converts plasminogen to plasmin, which breaks down the fibrin mesh and destroys the clot
examples of anticoagulants
heparin, warfarin (coumadin), direct thrombin inhibitors, factor Xa inhibitors
what is the primary drug for the initial treatment of venous thrombosis?
heparin
how must heparin be administered?
parenterally, usually through an IV
when is coumadin used?
long-term prevention of venous thrombosis
what is the difference in timing of the effects of heparin and coumadin?
heparin takes effect almost immediately, coumadin takes several days to be effective (patient may take heparin while waiting for coumadin to set in)
what is acceptable clotting range for INR?
clotting INR range: 2-3
adverse effects of anticoagulants
- hemorrhage
- back pain or joint pain (sign of internal bleeding)
- thrombocytopenia (decreased platelets)
- GI distress
- skin reactions
what is the function of antiplatelet drugs?
prevent excessive clotting caused by increased platelet activity (primarily for preventing arterial clots)
what is the effective dose for aspirin?
75-325 mg/day
how does aspirin affect strokes and DVT?
- helps prevent ischemic strokes
- may increase risk for hemorrhagic strokes
- can be used to prevent DVT
when are ADP Receptor Blockers used?
to prevent thrombosis in patients who are at risk for an MI or ischemic stroke (those with unstable angina, a-fib, etc.)
what is the function of Glycoprotein IIb-IIIa Receptor Blockers
they inhibit the ability of fibrinogen to activate platelets by blocking the receptor site on the platelet membrane
adverse effects of antiplatelet drugs
- increased risk of bleeding (frequent bruises)
- hypotension
- GI distress
- aspirin: gastric irritation, toxic to liver and kidney
function of fibrinolytics
they facilitate the breakdown and help to dissolve clots that have already formed, used for re-opening blood vessels
fibrinolytics and MI
- can reestablish blood flow when used at onset of MI (effective for 12 hours)
- decreases morbidity and mortality following an MI
- admin one hour after onset reduces mortality by 50%
when are fibrinolytics contraindicated?
- history of hemorrhagic stroke
- active internal bleeding
- other factors that increase risk for hemorrhage
what else can fibrinolytics be used for?
- dissolve DVTs
- PEs
- treat shunts and bypass grafts that have been occluded
what form of fibrinolytic activates plasmin to break down clots?
tissue plasminogen activator (t-Pa)
