Pharm Unit 2 - Anti-Thrombotics Flashcards
antiplatelets
prevent blood clot formation
primary hemostasis
endothelial injury
adhesion
activation
aggregation
endothelial injury
exposure of collagen and vWF inside vessel
adhesion
circulating platelets bind to vWF and collagen
activation
shape change of platelets
TXA2 release
granual release
GP IIb/IIIa conformation change
do platelets have nucleus?
no
TXA2 function
thromboxane recruits more platelets to the plug
expands the clot
what is converted into TXA2
arachadonic acid –> TXA2
what does granule release do
ADP
coagulation factors
aggregation
fibrinogen cross linking between platelets’ surfaces
anti-thombotic therapy goals
prevent thrombosis
without over promotion of bleeding
main risk of antithrombotics
bleeding
increase risk of death 3-5x
pt monitoring during antithrombotic therapy
Hgb drop
bloody stools
melena
hematuria
bruising
oozing from arterial/venous puncture
antiplatelets drug types
aspirin
P2Y12 receptor antagonists
GP IIb/IIIa inhibitors
Vorapaxar
aspirin mechanism
irreversibly inhibits COX-1
prevents conversion of arachidonic acid into thromboxane
- decr platelet formation
- decr vasoconstriction
aspirin uses
prevention of DVT
prevention of ASCVD (secondary)
- MI
- angina
- stroke/TIA
- PAD
- CAD
antiypyretic
analgesic
prevention of colorectal cancer
what is the fastest way to get aspirin into the body?
chew non-enteric coated
–20 mins
duration of aspiring effects
lasts entire platelet lifespan
wears off once new plts are made
aspiring SE
GI
bleeding
allergic rxns
incr hemorrhagic stroke in men
aspiring drug interactions
NSAIDs will blunt aspirins effect
incr risk of serious GI complications
ADP
binds to P2Y1
- incr Ca2+ == shape change
binds to P2Y12
- granule release
both paths activate GPIIb/IIIa, resulting in platelet aggregation
which is the more dominant ADP biding site?
P2Y12
so drugs target P2Y12
P2Y12 ADP inhibitor drugs
clopidogrel
prasugrel
ticagrelor
cangrelor
what polymorphism impacts clopidogrel?
decr CYP2C19 function
loss of effectiveness of drug
clopidogrel and prasugrel bind
irreversibly to P2Y12 receptor
which is more potent: clapidogrel or prasugrel?
prasugrel has more potent plt inhibition w/faster onset
clopidogrel is a prodrug so must be metabolized to work == slower
if you inhibit CYP2C19 function, would you amplify or reduce clopidogrels anti-platelet effect?
reduce
clopidogrel requires CYP2C19 to convert into active form
clopidogrel indications
acute coronary syndrome
- typically DAPT w/aspirin
percutaneous coronary intervention
- prevents stent thrombosis
2ndary prevention in atherothrombotic disease
- CAD
- CVD
- PAD
what drug can replace aspiring in prevention of atherothrombotic disease?
clopidogrel
Prasugrel CI
<60 kg = half dose
Stroke or TIA history
>75 yrs old
cannot be used in CABG pts
Prasugrel indication
only pts w/PCI and stent implant
Ticagrelor and Cangrelor bind
reversibly to ADP P2Y12 receptor
Ticagrelor and Cangrelor are administered
IV only
Ticagrelor: 2x daily
Cangrelor: continous IV
Ticagrelor is metabolized by
CYP3A
Ticagrelor vs Clopidogrel
ticagrelor has:
faster onset
more potent platelet inhibition
What other receptor does Tacagrelor block?
ENT1
– incr adenosine plasma levels
– incr endothelium function
– decr HR
Ticagrelor SE
dyspnea
– P2Y12 incr neuronal signaling
– incr conductivity of pulmomnary vagal C-fibers
– incr sensation of dyspnea
cangrelor bleeding rates compared to clopidogrel
cangrelor has higher bleeding rates compared to clopidogrel
cangrelor SE
dyspnea
decr renal function (3.2%)
Cilostazol mechanism
PDE3 inhibitor
incr intraplatelet cAMP
decr Ca2+
plt inhibition
Cilostazol effects
platelet inhibition
inhibit vascular smooth muscle cell proliferation
improves peripheral BF
Cilostazol indications
PAD - claudication
PVD
stroke/TIA
post-PCI
Cliostazol CI
HF
most abundant receptor on platelates
Gp IIb/IIIa
80,000 copies/plt
GPIIb/IIIa inhibitor mechanism
binds to GPIIb/IIIa receptors
prevents formation of fibrinogen plt-plt crosslinks
GPIIb/IIIa inhibitor indications
PCI
unstable angina
GP IIb/IIIa inhibitors SE
bleeding
thrombocytopenia
GP IIb/IIIa drugs
abcimimab
eptifibatide
tirofiban
GP IIb/IIIa inhibitor CI
active internal bleeding
major surgeries
recent trauma
intracranial hemorrhage
bleeding disorders
severe hypertension
abciximab has a ____ % risk of thrombocytopenia
5% risk
1% severe risk
anticoagulants
prevent blood clots from forming by interfering with coagulation factors
hemostasis
stopping bleeding
primary hemostasis
formation of platelet plug
secondary hemostasis
coagulation
extrinsic pathway of secondary hemostasis
activated by tissue factor found outside the blood
intrinsic pathway of secondary hemostasis
factors required for activation are found in the blood
common pathway
activation of factor X
coagulation cascade
4 parental anticoagulants
unfractionated heparin
low molecular weight heparin
synthetic pentasaccharides
direct thrombin inhibitors
parenteral anticoagulatns indications
DVT
PE
initial management of ACS