Wendt - AntiCoag Flashcards
role of plasmin?
degrades fibrin – and dissolves clot
all thromboembolytics work to increase the conversion of ______ to ______?
plasminogen; plasmin
What activates plasminogen to plasmin
t-PA
t-PA cleaves a ______ bond to activate plasmin
arg-val bond
Thrombolytics:
______ cleaves a arg-val bond to activate plasmin
t-PA
t-PA is inhibited by what things?
PAI-1 and PAI-2
plasmin is a ________ that digests fibrin and fibrinogen
proteolytic enzyme
Plasminogen is an anticoagulant protein that circulates in _______ form and is deposited on to a growing clot.
inactive
t-PA is known as a _______ protease
serine
plasmin is inactivated by _________
a2-antiplasmin
indications for thrombolytic therapy:
acute or chronic?
acute!
indications for thrombolytic therapy:
3 things
- acute MI
- acute ischemic thrombotic stroke
- PE
what are the 5 options of thrombolytic drugs
- Alteplase
- Reteplase
- Tenecteplase
- Streptokinase
- Urokinase
which thrombolytic drugs are known to be recombinant t-PA drugs
- Alteplase
- Reteplase
- Tenecteplase
Thrombolytic drug:
Streptokinase makes a complex with _______
plasminogen
Thrombolytic drug:
Streptokinase promotes ________ by the _________ molecule
promotes plasminogen activation; by adjacent plasminogen molecule
T or F: Streptokinase has intrinsic enzyme activity
FALSE! it does not directly degrade clots — it makes a complex that catalyzes conversion of inactive plasminogen to active plasmin
Anti-Fibrolytic Agents are?
- Lysine
- Tranexamic acid
- Aminocaproic acid (EACA)
plasmin binds to fibrin through a ______ binding site to activate fibrinolysis
lysine
anti-fibrinolytic agents are used to stop _____ caused by _______ drugs
stop bleeding; caused by thrombolytic drugs
how does plasminogen get converted to plasmin?
t-PA
how does Alteplase work?
its a thrombolytic drug that is a recombiant human t-PA
binds to fibrin
how does Reteplase work?
recombinant human t-PA
LESS FIBRIN specific/lacks fibrin binding domain
is Reteplase more or less fibrin specific than Alteplase?
less fibrin specific
is Tenecteplase more or less fibrin specific than Alteplase?
more specific!
Tenecteplase:
short or long 1/2 life?
long
-plase thrombolytic drug lacks fibrin binding domain
Reteplase
t-PA binds to _____ and activates bound ________ 100x more rapidly than in circulation
fibrin; plasminogen
Mutations in Tenecteplase lead to:
______ half life
reduce __________
enhance activity at ______
LONGER half life;
reduce INHIBITION by PAI
enhance activity at THROMBI
______ drug is a recombinant t-PA with the 527 aa residue
Altelplase
_______ drug is a recombinant t-PA with the 527 aa residue deletion
Reteplase
Anti-fibrinolytic agents act as a ________ to bind to the receptor on plasminogen and plasmin - leads to a ______ of plasmin binding to target fibrin
lysine analog; blockade
is Tranexamic Acid or Aminocaproic Acid (EACA) more potent as being a anti-fibrinolytic agent
Tranexamic Agent
do platelets have a nucleus?
no
are platelets made of granules?
yes
do platelets have organelles?
yes (but no nucleus)
Thrombus Formation is also known as what?
platelet plug or white thrombus
3 main steps for Thrombus formation are…
1 - platelet adhesion/Shape change
2 - platelet secretion
3 - Platelet aggregation
Thrombus Formation: STEP 1
Adhesion is mediated by what 2 things binding
GP1a; GP1b
GP 1a binds to ________
GP1b binds to _______
1a - collagen
1b - von willebrand factor (bridged to collagen)
Platelet adhesion mediated by:
_____ binding to collagen
_____ binding to VonWillebrand Factor (bridged to collagen)
________ facilitates receptor binding
GP1a
GP1b
Shape change
platelet adhesion:
intact ______ cells secret _____ to inhibit thrombogenesis
intact ENDOTHELIAL; secret PGI2 (prostacyclin)
Platelet secretion:
Platelet granules release what 3 things?
- ADP
- TXA2 (thromboxane A2)
- 5-HT (serotonin)
ADP, 5-HT, TXA2 activate and recruit what
other platelets
Platelet Aggregation:
ADP/5-HT/TXA2 activate/induce conformation of ______ receptors to bind _____
GP11b/111a receptors
bind fibrinogen
Platelets get cross linked by ______
fibrinogen
_____ is used to stabilize and anchor aggregated platelets
Fibrin
Platelet Activation:
1) _______ injury
2) exposed ______
3) Platelet ______
4) platelet _______
5) ______ activation
6) Platelet ______
7) Platelet ______
vascular injury exposed collagen adhesion activation integrin activation aggregation plug
what are the 5 options for Antiplatelet drugs
COX1 inhibitors ADP receptor inhibitors blockers of GP11b/111a receptors PDE3 inhibitors Protease Activated Receptor inhibitors
what drug is a COX 1 inhibitor
Aspirin
Aspirin (ASA):
inhibits platelet COX1 by ______
acetylation
Aspirin (ASA):
Blocks the conversion of ___ to ___
AA to PGG2
Aspirin (ASA):
Interferes with platelet ______
aggregation
Aspirin (ASA):
Prolongs _____ time
bleeding
Aspirin (ASA):
Prevents ________ formation
aterial thrombi
Aspirin (ASA):
Inhibition of _______ in platelets is the key to anti-platelet activity of ASA
TXA2 synthesis
Aspirin (ASA):
(reversible or irreversible) inhibition by acetylation of COX1
IRREVERSIBLE;
Aspirin (ASA):
end up having permanent loss of platelet cox1 activity bc of decreased ______
TXA2
Aspirin (ASA):
Irreversible inhibition by acetylation of _____
COX1
Aspirin (ASA):
(reversible or irreversible) inhibition by ________ of COX1
acetylation
at higher doses of aspirin, _______ production in tissue is inhibited
prostacyclin
T or F: aspirin increases PT time
FALSE (aspirin prolongs bleeding time but no PT time…)
is it used in Platelet Adhesion or Platelet Aggregation?
GP1a
platelet adhesion (binds to collagen)
is it used in Platelet Adhesion or Platelet Aggregation?
GP2a
platelet adhesion
is it used in Platelet Adhesion or Platelet Aggregation?
GP11b
platelet aggregation (it is an integrin)
is it used in Platelet Adhesion or Platelet Aggregation?
GP111a
platelet aggregation (it is an integrin)
what are the 2 ADP receptors involved in activating platelets
P2Y1; P2Y12
which ADP receptor is coupled to Gq-PLC-IP3-Ca2+ pathway
P2Y1
which ADP receptor is coupled to Gi & Inhibition of adenylyl cyclase
P2Y12
ADP comes from _______ and will bind to ______
from GRANULES;
binds to P2Y1 and P2Y12
what are the ADP receptor inhibitors (both direct and prodrugs)
Direct: Ticagrelo; Cangrelor
Prodrugs: Prassugrel; Clopidogrel; Ticlodipine
how do the “Thienopyridine” P2Y12 ADP receptors work?
irreversibly block ADP receptor on platelet & subsequent activation of GP11b/GP111a (action will last for a couple days)
Brand/Generic:
Prasugrel
Effient
Brand/Generic:
Effient
Prasugrel
Brand/Generic:
Brilinta
Ticagrelor
Brand/Generic:
Ticagrelo
Brilinta
How does Ticagrelor work?
binds to allosteric site;
REVERSIBLE binding
NOT a prodrug
which ADP receptors have REVERSIBLE binding AND do NOT require bioactivation
Ticagrelor (Brilinta)
Cangrelor (Kengreal)
what are the PDE3 inhibitors are used for decrease platelet activation
Dipyridamole; Cilostazol
how do PDE3 inhibitors act as an antiplatelet?
if cAMP levels are increased (which they are when PDE3 inhibitors are used) more cAMP leads to decreased intracellular calcium = decreases platelet aggregation and activation
do PDE3 inhibitors act as an antiplatelet or anticoagulant
antiplatelet
both Dipyridamole and Cilostazol:
work to inhibit ________ by prevent degradation of _____ to _____
PDE3; cAMP; AMP (equals more cAMP = equals less platelet aggregation)
which drugs are known as glycoproteins IIb/IIIA receptor inhibitors
- Tirofiban (Aggrastat)
- Abciximab (ReoPro)
- Eptifibitide
how does thrombin activate platelets
proteolytic cleavage of PAR-1 receptors on platelet surface
what drugs are known as Protease Activated Receptor Inhibitors
Vorapaxar
Atopaxar
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
COX1 Inhibitors
Anti-platelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Alteplase
Thrombolytic
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Aspirin
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Ticagrelor
Anti-Platelet
Brilinta/ADP Receptor Inhibitor
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Cangrelor
Antiplatelet
ADP Receptor inhibitor
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
ADP Receptor Inhibitors
Anti Platelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Cilostazol
Antiplatelet
PDE3 inhibitor
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
PDE 3 Inhibitors
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Dipyridamole
Antiplatelet
PDE 3 inhibitor
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Atopaxar
Antiplatelet
Protease Activated Receptor Inhibitor
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Warfarin
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Direct Thrombin inhibitor
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
t-PA analogs
Thrombolytic
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Direct Factor Xa Inhibitors
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Fondaparinux
AntiCoag
Indirect Factor Xa Inhibitors
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Rivaroxaban
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Apixaban
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Edoxaban
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Xarelto
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Eliquis
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Savasya
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Clopidogrel
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Prassugrel
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Ticlodipine
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Abciximan
Antiplatelet
GPIIB/GPIIIa receptor inhibitors
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Eptifibitide
Antiplatelet
GPIIB/GPIIIa receptor inhibitors
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Tirofiban
Antiplatelet
GPIIB/GPIIIa receptor inhibitors
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Tenecteplase
Thrombolytic
t-PA Analog
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Reteplase
Thrombolytic
t-PA Analog
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Protease activated receptor inhibitor
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
ADP receptor inhibitor
Antiplatelet
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Vit. K Antagonist
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Warfarin
Anti Coag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Heparin Agents
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Enoxaparin
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Dalataparin
Anticoag
Is it an Antiplatelet, Antiocoagulant, or a Thrombolytic Agent?
Vorapaxar
Antiplatelet
Protease activated receptor inhibitors
which GPIIb/GPIIIa receptor inhibitor is a chimeric mouse human monoclonal Ab
Abciximab
which GPIIb/GPIIIa receptor inhibitor is a
synthetic peptide
Eptifibitide
which GPIIb/GPIIIa receptor inhibitor is a nonpeptide tyrosine analogue
Tirofiban
GPIIb/IIIa Receptor is:
- known to be a receptor for ________
- known to anchor _______ to foreign surfaces and to each other
fibrinogen; platelets;
GPIIb/IIIa Receptors are activated by what 3 things?
TXA2 (thromboxane); thrombin; Collagen
Are GPIIb/IIIa Receptors take by oral or IV route
IV!
All clotting factors are made in the _____ (Except ________)
made in lifer; Except Von Willebrand Factor
Protein C: is it pro-coagulant factor or anti-coagulant
(self made) ANTI-coagulant
what is Transglutaminiase’s role in the clotting cascade
Cross link fibrin fibers
what are glycoproteins used for in the clotting cascade?
they are COFACTORs for activation of proteases
Factors XII, XI, X, IX, VII, II are known as _____coagulants that are work by cleaving down stream factors to activate them (aka a _________)
known as PRO-coagulant; they are SERINE PROTEASES
The extrinsic pathway needs ______ to get activated:
The intrinsic pathway needs ______ to get activated
Extrinisic - needs Tissue Factor
Intrinsic - collagen gets exposed in wall of the blood vessels
Notable things apart of the Extrinisc Pathway
Factors VII and X
Tissue Factor
what are the notable parts of the common pathway
X, Thrombin; Fibrin
Step by Step of Extrinsic Pathway:
- TF found on _________
- Factor VII normally resides in ______
- ____ binds to _____ to activate it
- Factor __ binds and cleaves factor ____
found on surface of cells outside; resides in blood;
TF binds to Factor VII (activates VII to VIIa)
VIIa binds/cleaves X
_______ changes fibrinogen to fibrin
Thrombin
Factor _____ changes prothrombin to thrombin
Factor Xa
______ activates factor XIII
Thrombin
Activated Factor XIII leads to _______
cross linking of fibrin = fibrin clot
What are some things that be produced by the body that prevent the coagulation cascade
- AT (antithrombin)
- Protein C:
- A tissue Factor Pathway Inhibitor
what is a POSITIVE Feedback mechanism for Regulating Coagulation
Thrombin!
what are the NEGATIVE feedback mechanisms for Regulating Coagulation
- Antithrombin
- Protein C system
- Factor Xa
How does Antithrombin act to DECREASE coagulation:
neutralizes procoagulant serine proteases (aka thrombin, Xa, IXa)
Antithrombin decrease coagulation is accelerated by ______
heparin
how does Protein C decrease coagulation
how does the system get activated and what does it do?
Protein C system gets activated by thrombin binding to thrombomodulin
Activated Protein C complex (APC) forms a complex with Protein S = inactivates factors Va and VIIIa
how does Factor Xa activate tissue factor pathway inhibitor
activates tissue factor pathway inhibitor (TFPI) to block initial activation of Factor VII
what drugs are direct factor Xa inhibitors
Rivaroxaban
Apixaban
Edoxaban
what drugs are direct thrombin inhibitors
Argatroban
Dabigatran
Bivalirudin
which drugs are vit. k antagonists
warfarin
Normal Prothrombin Time (PT)?
12 - 14 seconds
Normal aPTT?
26 - 33 seconds
Normal recalcification time?
2 - 4 minutes
aPTT or PT?
measures intrinsic pathway
aPTT
aPTT or PT?
measures extrinsic pathway
PT
Possible Tests for hemostatic function
- platelet count
- PT/INR
- aPTT
- D-Dimer
- Fibrinogen
warfarin inhibits _____ of vit. K
REDUCTION
why is it relevant that warfarin inhibits vit. K?
vit. k is essential for post translation modification of clotting factors
Warfarin inhibits ___________ thus blocking it to get back to its active form
Vit. K epoxide reductase
warfarin acts by inhibiting synthesis of which factors?
II, VII, IX, X
2,7,9,10
How is warfarin metabolized
in liver by CYP2C9
Idea behind Warfarin Necrosis:
Protein C decreases initially before the pro-coag levels decrease and puts pt at an increased risk for coagulation (esp of pt is protein C deficient before therapy)
use warfarin in pregnancy?
hellll no
what drugs decrease warfarins effect
- VIT K
- Cholestyramine
- Carbamazepine; Rifampin; Barbituates
what common drug can ENHANCE warfarins anticoag effects
Broad-Spectrum Abx
what drugs are low molecular weight heparins
Enoxaparin; Daltaparin
Heparin and heparin related drugs are known as ____________ inhibitors
indirect factor Xa