blood thinners Flashcards
Thrombotic disorders such as acute myocardial infarction, deep vein thrombosis, pulmonary embolism, and acute ischemic stroke are treated with what drugs?
Thrombotic disorders such as acute myocardial infarction, deep vein thrombosis, pulmonary embolism, and acute ischemic stroke are treated with drugs such as anticoagulants and *fibrinolytics
Coagulation involves what?
Coagulation involves both cellular (platelet) and protein-based (coagulation factors) components
Arterial thrombosis usually consists of what?
Arterial thrombosis usually consists of a platelet-rich clot
antihemostatic agent drug classes
anticoagulents and platelet inhibitors
whats an example of a fibrinolytic?
TPA (tissue plasminogen activator) - utilized in hospital setting; used for pt with MI
The coagulation process culminates in the generation of thrombin which stimulates what?
The coagulation process culminates in the generation of thrombin which stimulates conversion of fibrinogen to the glycoprotein fibrin
The cascade consists of ___ interrelated pathways
The cascade consists of two interrelated pathways
Drugs acting within the extrinsic pathway (which is most important in vivo) affect the synthesis of what?
Drugs acting within the extrinsic pathway (which is most important in vivo) affect the synthesis of vitamin K- dependent coagulation factors
Drugs acting within the intrinsic pathway
inhibit the activity of what?
coagulation factors
what does the extrinsic pathway lead to?
rapid accummulation of thrombin (which is last step to convert fibrin)
*most efficacious part
whats most important about the intrinsic pathway?
minor role in clot activation and is more important in inflammation pathways (tissue injury)
how can intrinsic cascade start?
blood vessel injury –> subendothelial tissue factor in bv –> leads to activation of factor 7 –> starts intrinsic cascade
what are the three pathways?
intrinsic
extrinsic
common
2 antagonists
vitamin k and coagulation factor
which of the 2 antagonists is an indirect drug
vitamin k antagonist –> cofactor that combines with decarboxylase enzyme –> carboxylation (activation) of tissue coagulation factors –> vitamin k is oxidized (not useful)–> vitamin k epoxide reductase –> reduces vitamin k back to original state
vitamin k antagonist
coumadin (warfarin)
indication for coumadin
anticoagulation dosing (2-10 mg) 1 tab qd
most widely prescribed anticoagulant in usa
coumadin
Inhibits vitamin K-dependent coagulation factor synthesis (II, VII, IX, X, proteins C and S)
moa of coumadin
which coagulation factors are inhibited by vitamin k?
7, 9, 10
warfarin is important because?
it can affect both pathways?
trauma activates what pathway
extrinsic
damaged surface (vessel) activates what pathway?
intrinsic
are vitamin k and potassium the same thing?
no
whats the christmas factor?
9
11 –> 9 –> 8 are wat?
3 hemophilias
9 and 8 are associated with what disease?
x linked disease
11 is associated with what?
hemophelia type c (autosomal recessive) –> found in isolated pops
if you have an infection what pathway is activated?
intrinsic????
isolation of microbes –> enhanced bf for leukocytes –> all liked to inflammation process
vitamin k epoxide reductase regenerates what?
new vitamin k
if we cut off vitamin k what happens?
neither pathways are able to generate fibrin clots, because prothrombin depends on vitamin k
ADVERSE EFFECTS
• Common: Bleeding/bruising, headache, dizziness, pruritus, edema, dermatitis, fever, paresthesias, alopecia
coumadin adverse effects
SERIOUS
CV: syncope, vasculitis, hemorrhage, cholesterol embolism
• Hematology: anemia
coumadin serious adverse effects
what ocular disease do we treat tetracycline with?
MGD; gram positive
WHAT If pt is taking coumadin and tetracycline?
pt will bleed to death because tetracycline will impair metabolism of drug
name 2 coagulation factor antagonists
- Enoxaparin [Lovenox®, Xaparin®, Clexane®]
* Rivaroxaban [Xarelto®]
indication for enoxaparin
Post-op DVT prophylaxis,
Unstable Angina
DOSING [30-40mg] • 30mg SC bid; 40mg
how is enoxaparin administered?
injection
enoxaparin moa
binds to antithrombin 3 and accelerates its activity; inhibiting thrombin and factor (xa)
*acts as a stimulant for antithrombin and and antagonist to coagulation
whats heparin used for?
in hospital settings
heparin sequence
heparin binds to antithrombin –> (thrombin + factor 10a) binds to heparin combo –> takes it out of activity
lmw heparin sequence
lmwh –> binds to antithrombin –> combo binds to factor xa
why is lmwh preferred over regular heperin?
yes because heperin has an unpredictable response due to its length
is lmwh activity predictable?
yes
pros of lmwh
half life is 4 hours, predictable response, 90% bioavailability, less frequent bleeding, hospital and outpatient
can heperin be used outside of hospital settings
yah its better than enoxaparin
adverse effects of enoxaparin
hemorrhage and fever
serious adverse effects of enoxaparin
anemia
Platelet aggregation inhibitors decrease what?
Platelet aggregation inhibitors decrease the formation or the action of chemical signals that promote platelet aggregation
The platelet membrane GP IIb/IIIa receptor which is activated in the critical last phase of thrombus formation serves to what?
The platelet membrane GP IIb/IIIa receptor which is activated in the critical last phase of thrombus formation serves to bind adhesive proteins like fibrinogen
• Platelet stimulating agents that lead to GP IIb/IIIa receptor activation include what?
• Platelet stimulating agents that lead to GP IIb/IIIa receptor activation include Thromboxane-A2, ADP, thrombin, serotonin, and collagen
platelet aggregation inhibitors inhibit cox-1, block
which receptors?
platelet aggregation inhibitors inhibit cox-1, block
adp receptors or GP 11b/111a receptors
membrane phospholipids –> arachidonic acid –> prostaglandin H2 –> thromboxane A2
TXA2 activation
where does COX1 act in inflammation pathway?
stops arachidonic acid from turning into TXA2
pgi2
antiinflammatory involving inhibitition of platelets and vasodilator
2 platelet inhibitor drug classes
- Adenosine Receptor Blockers
- Glycoprotein IIb/IIIa Receptor Antagonists
- Clopidogrel [Plavix®]
- Ticlopidine [Ticlid®]
- Prasugrel [Effient®]
- Dipyridamole [Persantine®]
adenosine receptor blockers
INDICATION
• Acute Coronary Syndrome, Thrombotic
Event Prophylaxis
• DOSING [75 & 300mg] • 1 tab qd
clodipogrel
whats the reason a patient will show up at our optometry office indicating use of clopidogrel?
thrombotic event prophylaxis
CLINICAL PHARMACOLOGY • Antiplatelet
Mechanism of Action
• Prodrug: metabolized to active metabolite by the CYP450 enzyme CYP2C19*
• Irreversible inhibition of platelet ADP receptors which normally trigger platelet activation and aggregation via downstream activation of the GPIIb/
IIIa complex
moa of clopidogrel
irriversible inhibition is shown in what drugs?
NSAID and clopidogrel/ticlopidine
• Common: hemorrhage, pruritus, cough, bronchitis, dizziness, headache
SERIOUS ADVERSE EFFECTS
• Hypersensitivity: Angioedema, SJS, TEN
• Hematology: TTP

adverse effects of clopidogrel
• Evening Primrose Oil, Flaxseed, Omega-3 FA, NSAIDs (Additive)
• Ketoconazole (Reduced metabolism/ activation)

clopidogrel drug interactions
mab
monoclonal antibody-drug that has been engineered; purified pool of ab that are monoclonal specific for an antigen
caution: ocular disease
clopidogrel
Abciximab [ReoPro®]
• Eptifibatide [Integrilin®]
gp 2b/3a receptor antagonists
- INDICATION
- An adjunct to percutaneous coronary intervention (PCI) for the prevention of cardiac ischemic complications
- Unstable angina
DOSING [Variable]
• IV bolus (all at once-very rapid)
abciximab
clinical pharm: antiplatelet
moa
Fab fragment: a chimeric human-murine mAB
-binds to the GP 2b/3a receptor of human platelets and inhibits platelet aggregation
-binds to the vitronectin (avb3) receptor on platelets and vessel wall endothelial and smooth muscle cells
moa of abciximab
Common: hemorrhage, hypotension, dizziness, headache
adverse effects of abciximab
Omega-3 & Omega-6 fatty acids, NSAIDs (Additive)
• Ophthalmic NSAIDs (Additive)
drug interactions of abciximab
- recent surgery or trauma
- uncontrolled hypertension
abciximab contraindications
