Antithrombotics Flashcards by Joshua Layton

What are the 3 phases of blood Hemostasis?

Vascular spasm
Platelet plug formation
Coagulation

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What are the three major drug classes of antithrombotics?

Antiplatelets
Anticoagulants
Fibrinolytics

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What do antiplatelets mainly work on? What is another name for them?

Mainly work on arteries

Blood thinner

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What are the 2 routes anticoagulants are given? What vessel do they mainly work on?

Oral
Parenteral

Mainly work on veins

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What is the only route that fibrinolytics are given?

Parenteral

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What type of receptor is P2Y12?

ADP receptor

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What type of receptor is TP?

Thromboxane receptor

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What type of receptor is G2b/3a?

Fibrinogen receptor

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What type of receptor is GP1B?

vWF receptor on platelets

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What activate a platelet?

Thromboxane

ADP

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What are the 3 things that platelet activation causes?

Change in platelet shape
Express active fibrinogen receptor
Release thromboxane and ADP

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How can an NSAID help fight clotting?

NSAID is COX inhibitor

Inhibits thromboxane

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How is an antiplatelet used for MI and strokes?

Prophylactically

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Why are antiplatelet drugs used for unstable angina?

Because angina make you more prone to clotting and antiplatelets prevents platelets from being activated and sticking together

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Why are antiplatelets used for acute MIs?

To prevent further clot forming

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Why are antiplatelets used for precutaneous coronary intervention(ie angioplasty)?

To thin out blood during surgery

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What are the 4 indications for antiplatelets?

MI and stroke prevention
Unstable angina
Acute MI
percutaneous coronary intervention

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How does the intrinsic pathway start?

Collagen activating factor 12

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What starts the extrinsic pathway?

Tissue thromboplastin activates factor 7

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What is another name for tissue factor? Where is it released from?

Tissue thromboplastin

Released from subendothelial cells

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What is needed to convert prothrombin into thrombin?

Factor 10a
Factor 5a
Ca2+

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What turns fibrinogen into fibrin? Which is more soluble in blood?

Thrombin turns fibrinogen into fibrin

Fibrinogen is more soluble in the blood

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What are the 4 different types of anticoagulant drugs?

Heparins
Vitamin K antagonists
Direct factor 10a inhibitors
Direct thrombin inhibitors

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Where do natural heparins come from?

Liver

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What are the 2 different types of heparins?

Unfractionated heparin | Low-molecular weight heparin

What route is heparin given?

IV | SC

What does aPTT stand for? What does it test? What medication is it used to monitor?

Activated partial thromboplastin time Tests intrinsic pathway and common pathway Used to monitor Heparin

What is used to prevent blood from clotting for aPTT

Citrated plasma

What is a normal aPTT? What is the aPTT for a pt on heparin?

25-35 seconds | 45-70 seconds

What is added to blood in order to measure an aPTT(3)?

Ca2+ Kaolin Phospholipids

What is the MOA of Heparins?

It enhances antithrombin 3 activity

What does antithrombin do?

Decreases activity of factor 10 and thrombin

What are heparins indicated for? What can heparins be used for the management of?

VTE Stasis of blood Endothelial damage Hypercoagulable conditions Unstable angina Coronary angioplasty Cardiopulmonary bypass tubing

Why can endothelial damage lead to a VTE?

Because these damages are usually caused by surgeries that increase the risk of DVT or PE

What are two conditions that can cause hypercoagulability?

Burn wounds | DIC

How does heparin help unstable angina?

Breaks down clots

How does heparin help w/ coronary angioplasty?

Used during the surgery to prevent clots from forming

How does heparin help when cardiopulmonary bypass tubing is being placed in a body?

Heparin prevents tubing from activating clotting cascade

What percent of unknown deaths are d/t PE?

80%

What does HIT stand for? What does HITT stand for? How is it caused?

Heparin induced thrombocytopenia Heparin induced thrombocytopenia w/ thrombosis IgG/PF-4/Heparin complex forms to cause either - thrombocytopenia...leading to bleeding - thrombosis...leading to clot forming

If HITT/HIT is suspected in a pt, what should be done w/ the heparin?

Discontinue heparin

What signs can suggest the presence of HIT/HITT?

Skin lesions at injection site | Acute systemic reaction

What type of heparin is used during pregnancy?

LMWH

What are the number of units used for a central line IV catheter lock flush of heparin? What are the units for a full dose of heparin?

1-100 units /mL 1000-40,000units/mL

What is a coumarin?

Vitamin K antagonist

What is a coumarins/vitamin K antagonist MOA?

Inhibits VKOR in the liver which turns vitamin K into active vitamin K which helps makes certain clotting factors

How long does it take for warfarin(Coumadin) to have a full anticoagulant effect? What is given before warfarin kicks in?

2-3 days Overlapped w/ heparin till warfarin has effect

What are the indications for warfarin(Coumadin)?

- Tx and prevention of VTE - Tx and prevention of thromboembolism d/t A-Fib or prosthetic heart valves - prevention of post MI

Why can A-fib cause a thromboembolism?

Blood that is not moving tends to clot

What can prosthetic heart valves cause thromboembolism?

Because they can cause stasis of blood and lead to clots

Why is pregnancy a contraindication for warfarin(Coumadin)?

Because it can cross the placenta and cause hemolytic disease of newborns

What is the antidote for warfarin(Coumadin)? Route?

``` Vitamin K( phytonadione) Fresh frozen plasma ``` IM SC

What is a food that is pro vitamin K?

Leafy greens

Why is warfarin more beneficial then direct oral anticoagulants?

- has antidote - INR is monitored - can be used for pt w/ heart valve issues - costs less

What is PT? What pathway is it used to measure? what is it used to monitor? What units is it measured in?

Prothrombin time (pro time) Measures time to clot for extrinsic and common pathway Monitors pt on warfarin INR

If a pt has a high INR what does that mean for anticoagulant effect?

Higher INR=higher anticoagulant effect

What is the INR for a pt on warfarin?

2-3 INR

What is used to bind up Ca2+ in blood when measuring a PT?

Citrated plasma

What is put into blood to start measuring a PT?

Ca2+ | Thromboplastin

If a pt has a too high of an INR what should be done w/ the next warfarin dose?

Hold the warfarin dose

What should be given if a pt has a warfarin-associated major bleed?

PCC FFP Vitamin K

What does PCC stand for? What does it do?

Prothrombin complex concentrate Makes clotting easier

What Sx can becoming present if INR is too high

``` Hematuria (blood in urine) Melena (blood in stool) Petechia (pinpoint hemorrhage) Ecchymoses (bruising) Purpura (medium hemorrhages) ```

Where does our vitamin K sources come from?

Food=50% | Bacteria in large intestine=50%

What 3 conditions can affect clotting?

Alcoholism Kidney disease Liver disease

What drug can interfere w/ warfarin or heparin?

NSAIDs

What should be done before warfarin is given? What should be done before giving heparin?

Take a PT/INR test Take aPTT test

Before poking an individual on anticoagulants make sure you know what?

Make sure you know the pts INR

What is a direct factor 10a inhibitor considered?

Direct oral anticoagulants

What is a warning for pts taking direct factor 10a inhibitors?

Epidural catheters w/ these drugs can cause potential spinal hematomas

What is the 3 contraindication for direct factor 10a inhibitors?

Any heart valve issue Active bleeding Pts w/ increased risk of bleeding

What are the 2 indications for direct factor 10a inhibitors?

- Tx and prevent VTE | - thromboembolism

What is more beneficial for a pt on direct factor 10a inhibitors than taking an anticoagulant?

No monitoring required (no PT or aPTT taken)

What is direct thrombin inhibitors MOA?

Inhibits thrombin from turning fibrinogen into fibrin

What are two other names for fibrinolytics?

Thrombolytics | Clot busters

What is the MOA of a fibrinolytic? Route?

Increases plasmin production which breaks down fibrin IV

What are endogenous forms of fibrinolytics?

tPA | Urokinase

What is fibrinolytics indicated for?

Acute MI PE Thrombotic strokes

What are contraindications of fibrinolytics?

Hemorrhagic stroke