Module 5 - 1 Flashcards
Antiplatelete
inhibit the initiation of a clot
Anticoagulants
prevent formation of a mature clot (but they cannot dissolve a clot where one has already formed)
thrombolytics
are used to dissolve clots that have already formed
when bleeding occurs in the body, three mechanisms reduce blood loss
- Vascular spasm
- Formation of a platelet plug - platelet inhibitors
- Blood clotting (coagulation) - anticoagulants
Drugs that dissolve clots
“clot busters” are tissue plasminogen activators (tPA)
Thrombus
clotting in an unbroken artery or vein is called a thrombus, and the abn disease process that accounts for it is called “thrombosis”
*** Thrombus is like skaters on a very rough surface. may become dislodged and be swept away in the blood.
Abnormal thrombi
in “arteries” are usually initiated by a roughened, diseased surface of a blood vessel, such as occurs form atheroscherosis, trauma or infection
DVT
Deep Venous Thrombosis
abn thrombotic clots that from the the “veins” usually happens when blood flows too slowly (stasis), allowing clotting factors to accumulate and initiate coagulation.
embolus (pl. emboli)
when an atherosclerotic thrombus, blood clot, air bubble, or piece of fat or other debris is transported by the bloodstream.
thromboembolic events
thrombosis and embolism can be understood as being part of the same disease. this lead to partial blockage, decreased blood flow, and chest pain
The most serious types of thrombus
is when blood clots on top of an unstable atherosclerotic plaque
The most serious type of embolus
is when the clot/plaque breaks free as an embolus
what are the three different types of anti-clotting drugs?
- Platelet Inhibitors
hinder the ability of platelets to get sticky and form a platelet plug - Anticoagulants
of the “deep clotting cascade” - hinder one or more steps in the cascade of soluble clotting factors that lead to the formation of thrombin - Thrombolytics - the “clot buster” drugs dissolve a clot after it has already formed
Antiplatelet drugs are used to:
- Prevent or treat superficial venous thrombosis, and more mild cases of DVT
- Prevent the “mini-strokes” that are called TIAs that often presage an impending stroke
- Prevent and treat anginal chest pain that often presage an impending MI
- All platelet inhibitors work making platelets less sticky
Aspirin - platelet inhibitor
NSAID is placed into the catergory of anti-clotting drugs
prophylaxis to relieve angina and prevent heat attacks and stroke.
clopidogrel (Plavix)
Platelet Inhibitors prescription - currently the 2nd best selling drug worldwide
Platelet inhibitors drugs side effect
Bruising. Any bleeding seen from platelet inhibitors is sometimes called “superficial bleeding” - bloody nose
Anticoagulation drugs side effect
Deep Bleeding - bleeding into the joints, the abdomen, or brain (if pt on Coumadin)
Coumadin adverse effect (anticoagulant)
bleeding into joints, the abdomen, or brain (brain hemorrhage)
Bleeding Time (BT)
A test of superficial bleeding that can be used to demonstrate the effects of platelet inhibition.
Anticoagulants are powerful drugs used to:
- provide anticoagulation during hemodialysis and cardiopulmonay bypass (CPB)
- prevent or treat DVT or pulmonary embolism (PE - which is related to DVT)
- Prevent or treat “Stroke” or the recurrence of stroke
- Prevent or treat MI or the recurrence of MI
- they all work by interrupting one or more of the clotting steps depicted in the following diagrams
Coagulation cascade
anticoagulants impede the deep system of coagulation cascade through the:
- Extrinsic pathway
- Intrinsic pathway
- common pathway
PTT test
to measure the heparins (anticoagulant) administered - inhibition of the “intrinsic pathway”
INR (PT) test
to measure the “Coumadin” (anticoagulant) administered - inhibition of the “extrinsic pathway”
Pradaxa (dabigatran)
direct thrombin inhibitors - common pathway, no test for this drug
Heparins
stimulates our own natural anticoagulant called antithrombin III of the deep clotting cascade - best seen by checking the aPTT test. I.V
Enoxaparin (Lovenox)
is low molecular weight heparins (LMWH) drug can be treat outpatients (NO HOSPITALIZATION) and don’t require blood tests (PTT) to monitor coagulation status
Coumadin (warfarin) = RAT POISON
is an inhibitor of vitamin K dependent clotting factor made in the liver. measuring the “extrinix clotting pathway by INR (PT) test to confirm Coumadin’s effects in pt taking the drug - Oral only
FFP
FRESH FROZEN PLASMA - since Coumadin inhibits vitamin K which is essential for some clotting to function, a vitamin -K injection or administration of FFP will counteract its effects and bring the coagulation state back to normal.
The newest group of anticoagulants
Pradaxa (dabigatran)
- Faxtor Xa inhibitors
- Direct Thrombin Inhibitors (DTIs)
Pradaxa (dabigatran)
Factor Xa inhibitor and Direct Thrombin Inhibitor
plasminogen
when clots are formed, a lot of the natural protein plasminogen is incorporated into the clot in preparation for them time when the clot will need to be dissolved.
t-PA - r-tPA
Tissue plasminogen activator - “Clot buster”
***t-PA convert plasminogen into an active enzyme (plasmin) which breaks apart the clot
Thrombolytic drugs - when to use it
accelerate the normal “clot busting” process by augmenting the action of t-PA.
are used in situation where immedicate clot lyse is absolutely necessary to save a life
- An acute heart attack
- A thrombotic or embolic stroke
* * they cannot be use in cases of a stroke caused by hemorrhage of blood (hemorrhagic stroke)
Thrombolytic drugs
used through a catheter inserted into a coronary artery to bust a clot…maybe save a life
alteplase (Activase)
this is a r-tPA drug (recombinant t-PA) the first t-PA approved by FDA 1996.
