Module 4: Unit C Antithrombotic Flashcards
Can pregnant people take warfarin (Coumadin)?
No. Can cause “fetal warfarin syndrome”
How do you handle a missed dose of warfarin (Coumadin)?
Do not double dose to make up for missed doses
Drugs that increase (more likely to bleed) Warfarin’s effect:
Amiodarone, Antiplatelets, NSAIDs, Macrolides, and Thyroid hormones.
Which populations require lower warfarin dosing?
elderly, heart failure, malnourished, liver disease, with certain drugs
What important patient education is indicated for people on warfarin (Coumadin)?
A consistent diet of leafy greens (Do not limit).
Do not double dose to make up for missed doses. Always tell all providers (including dentists)
Contact your provider ASAP for bleeding.
Do not take ASA or NSAIDs
Example AnticoagulantVitamin K antagonist
Warfarin (Coumadin)
Indications for Anticoagulant-Vitamin K antagonist
(warfarin)?
Main: Long-term prevention of venous thrombosis/PE
pts. w/ prosthetic heart valves
AFIB
MOA Anticoagulant-Vitamin K antagonist
(warfarin)?
Inhibits enzyme needed to convert vitamin K into the active form, resulting in ↓ the production of factors VII, IX, X, and prothrombin, ultimately ↓ fibrin formation.
Contraindications and considerations with prescribing Anticoagulant-Vitamin K antagonist
(warfarin)?
Contraindicated in pregnancy uncontrolled bleeding disorders Caution in liver disease, vitamin K deficiency Significant interactions with many classes of drugs-see list
BBW for Anticoagulant-Vitamin K antagonist
(warfarin)?
It can cause major or fatal bleeding.
Monitor INR-weekly until stable then q4 weeks
Dietary counseling for Anticoagulant-Vitamin K antagonist
(warfarin)?
There are many D2D interactions, including several herbal interactions. The “G” herbs: garlic, ginger, ginkgo, and ginseng, green tea, fish oil. Leafy green vegetables.
Consistent diet!!
Monitoring required with Anticoagulant-Vitamin K antagonist
(warfarin)?
Monitor PT/INR, range 2-3 most common
Monitor INR-weekly until stable then q4 weeks
How do you treat a Anticoagulant-Vitamin K antagonist
(warfarin) OD?
Vitamin K
Example of Anticoagulant Unfractionated Heparin (UFH)
Heparin
Indication for Unfractionated Heparin (UFH)?
Prophylaxis of venous thrombus
DVT, PE, DIC, MI
Open heart surgery and renal dialysis to prevent coagulation in devices
Prevent post-op thrombus
MOA Unfractionated Heparin (UFH)?
↓ coagulation by enhancing antithrombin’s ability to inactivate thrombin and factor Xa, ultimately ↓ fibrin formation
BBW Unfractionated Heparin (UFH)?
↑ risk of spinal or epidural hematoma
caution before, during, and after spinal surgery as well as eye & brain
What conditions/situations is Unfractionated Heparin (UFH) contraindicated in?
bleeding disorders, thrombocytopenia, lumbar puncture, epidural. Not used in primary /ambulatory care. Typically reserved for the inpatient setting.
Adverse effects of Unfractionated Heparin (UFH)?
3 H’s:
Hemorrhage
Hyperkalemia
Heparin-induced thrombocytopenia (HIT)
Heparin and Lovenox reversal agent
protamine sulfate
What anithrombotic is preffered in pregnancy?
Heparin. (Lovenox specifically-LMWH). The large molecule does not pass the placenta or breastmilk.
What lab values do we need to monitor with heparin?
Potassium
aPTT and adjust dosage accordingl
Example of Low-molecular-weight heparin (LMWH)
Lovenox
dalteparin (Fragmin)
Indication for Low Molecular Weight Heparin (LMWH)?
DVT
PE
STEMI,
NQWMI
MOA LMWH (lovenox)
inactivating factor Xa, ultimately ↓ fibrin formation
BBW LMWH (Lovenox and Fragmin)?
↑ risk of spinal or epidural hematoma-caution before, during, and after spinal surgery as well as eye & brain
LMWH (Lovenox and Fragmin) are contracindicated in
uncontrolled bleeding disorders, severe thrombocytopenia
Adverse effects of LMWH (Lovenox)?
↑ risk hemorrhage
Can cause immune-mediated thrombocytopenia
Does aPTT need to be monitored in LMWH (Lovenox)?
No
Direct Oral Anticoagulants (DOACs) Direct thrombin inhibitor Example
dabigatran (Pradaxa)
Indication for DOACs [dabigatran (pradaxa)]?
Prevention of stroke/embolism in AFIB,
prevention of VTE after knee or hip replacement
DVT PE
MOA for DOACs [dabigatran (pradaxa)]?
Direct, reversible thrombin inhibitor which prevents:
conversion of fibrinogen into fibrin
and activation of Factor IIIa (blocks conversion of soluble fibrin into an insoluble form)
Safety considerations for DOACs (Pradaxa)?
Bleeding, GI disturbances: dyspepsia, gastritis s/s
P-glycoprotein inhibitors (like ketoconazole, amiodarone, verapamil, and quinidine) can ↑ level of dabigatran with ↑bleeding risk.
BBW for DOACs (Pradaxa)?
Spinal/Epidural hematomas.
Reversal agent for DOACs (Pradaxa)
idarucizumab (Praxbind)
Anticoagulant-Direct Factor Xa inhibitors example
-XABANs:
rivaroxaban (Xarelto)
apixaban (Eliquis)
betrixaban (Bevyxxa)
edoxaban (Savaysa)
indication for Direct Factor Xa inhibitors (xarleto, eliquis, bevyxxa, savaysa)
Prevention of:
DVT/PE (after hip/knee surgery, recurrent, random)
Stroke w/ AFIB,
Moa for for Direct Factor Xa inhibitors (xarleto, eliquis, bevyxxa, savaysa)
Selective inhibition of factor Xa, which inhibits the production of thrombin, ultimately ↓ fibrin formation.
Safety considerations for Direct Factor Xa inhibitors (xarleto, eliquis, bevyxxa, savaysa)? Who should have cuation?
Bleeding risk.
Levels can increase in the presence of drugs that ↓ CYP3A4 or P-glycoprotein.
Caution with renal and hepatic impairment which can ↑ level and bleeding risk (monitor renal regularly)
Unsafe in pregnancy
BBW for Direct Factor Xa inhibitors (xarleto, eliquis, bevyxxa, savaysa)
Premature discontinuation increases the risk of thrombotic events.
Spinal/Epidural hematomas.
Monitoring required for Direct Factor Xa inhibitors (xarleto, eliquis, bevyxxa, savaysa)
Kidney function
Baseline and regular monitoring of kidney function to decrease risk of bleeding if renal excretion is delayed
Reversal agent for Direct Factor Xa inhibitors (xarleto, eliquis, bevyxxa, savaysa)
andexanet alfa (Andexxa)
Example of Antiplatelet-
cyclooxygenase inhibitor
aspirin
indication for cyclooxygenase inhibitor (aspirin)?
Many indications
Prevention of arterial thrombosis
Ischemic CVA/TIA,
acute and prior MI, 1° and 2° prevention MI, unstable angina
coronary stenting,
MOA cyclooxygenase inhibitor (aspirin)?
Irreversibly inhibits cyclooxygenase for the life of platelet (7-10 days), which ↓ synthesis of TXA which suppresses TXA mediated platelet aggregation and vasoconstriction
Safety considerations with cyclooxygenase inhibitor (aspirin)?
↑ risk of GI bleeding and hemorrhagic stroke, even at a low dose and with enteric coatings
BBW cyclooxygenase inhibitor (aspirin)?
Do not use in poor metabolizers as those with variant CYP2C19 gene cannot reliably convert this drug to its active form. This can lead to cardiovascular events.
Examples of Antiplatelet
P2Y12 ADP Receptor Antagonist
GRELS
clopidogrel (Plavix)
prasugrel (Effient)
ticagrelor (Brilinta)
indication for P2Y12 ADP Receptor Antagonist (Plavix, Effient, Brilinta) -GRELs
Prevent stenosis of coronary stents.
2° prevention of MI, ischemic CVA
MOA for P2Y12 ADP Receptor Antagonist (Plavix, Effient, Brilinta)
Blocks P2Y12 ADP receptors on platelets which prevent ADP-mediated platelet aggregation. Action is irreversible for the life of the platelet (7-10 days).
BBW with P2Y12 ADP Receptor Antagonist (Plavix, Effient, Brilinta)
Poor metabolizers: patients with variant forms of CYP2C19 cannot predictably convert clopidogrel to an active form. Genetic testing and platelet monitoring are recommended.
Indication of antiplatelet dipyridamole (Persantine)
prevent post valve thromboembolism
MOA of dipyridamole (Persantine)
↓ Adenosine deaminase and phosphodiesterase which↑ adenosine, adenine nucleotides, and cyclic AMP and ↓ platelet aggregation. May cause vasodilation
Safety with dipyridamole (Persantine)
bleeding,
can precipitate/exacerbate angina
HA, dizziness, GI
What is aggrenox?
A combination of ASA and dipyridamole (persantine) used to prevent ischemic stroke and TIA
indication for cilostazol (Pletal)
Intermittent claudication (pain in legs, usually during exercise)
MOA of cilostazol (Pletal)
↓ platelet aggregation and promotes vasodilation (mostly in legs) by inhibiting PDE-3 in platelets and blood vessels
Safety with cilostazol (Pletal)
HA, dizziness
↑ risk of infection
rhinitis
GI upset
Cardiac: palpitations and dysrhythmias
What is cilostazol (Pletal) often combined with?
ASA or Plavix.
What patients should not use antithrombotics?
Do not prescribe in situations where patients are at high risk for bleeding. This would include a recent hemorrhagic stroke, risk of active major bleeding, or recent trauma.
What is heparin-induced thrombocytopenia?
an antibody-mediated coagulopathy due to heparin exposure that is associated with a risk of thromboembolic complications and death. The only treatment is to stop the heparin.
What is the treatment for HIT?
Stop the heparin!
