Anticoagulation Flashcards
What is an embolus?
When a clot or a piece of a clot travels to another location
What factors does warfarin inhibit?
SNOT Seven Nine Ten (10) Two
What factors do rivaroxaban, apixaban, edoxaban, and betrixaban inhibit?
Xa
All have xa in their name
What factors do UFH inhibit?
Xa and IIa
What factors do LMWH inhibit?
Xa and IIa (more X than II)
What factors do argatroban, bivalirudin, and dabigatran inhibit?
IIa (thrombin)
DOAC vs Warfarin
Which has less drug drug interactions?
DOAC
DOAC vs Warfarin
Which has shorter half life?
DOAC
DOAC vs Warfarin
For which one is dosing based on the indication and liver/hepatic function?
DOAC
DOAC vs Warfarin
Which one is dosed based on INR?
Warfarin
When to use DOAC vs Warfarin
DOAC: stroke prophylaxis in afib if CHADSVASC >/ 2 (men) or 3 (women); VTE treatment
Warfarin: if moderate/severe mitral stenosis or mechanical heart valve
If patient has cancer and VTE, use LMWH
What factor does fondaparinux inhibit?
Xa indirectly via antithrombin
What is the drug of choice in someone with HIT?
argatroban
What decrease in Hgb can indicate a bleed?
> /2
What drugs increase bleeding risk?
Anticoagulants, antiplatelets, NSAIDs, natural products (e.g. ginkgo), SSRIs, SNRIs
Unfractionated heparin MOA
binds to antithrombin (AT) which inactivates factor IIa (thrombin) and Factor Xa and prevents the conversion of fibrinogen to fibrin
Unfractionated heparin prophylaxis and treatment of VTE dosing - use what body weight?
Prophylaxis: 5000 units SQ q8-12h
Treatment: 80 units/kg IV bolus then 18 units/kg/hr
Use total body weight
Unfractionated heparin CI, Warnings, SE
CI: active bleeding, severe thrombocytopenia, history of HIT
Warnings: Fatal medication errors
SE: Bleeding, thrombocytopenia, HIT, alopecia, hyperkalemia, osteoporosis (long term use)
Unfractionated heparin antidote
protamine
Why should you not given unfractionated heparin IM?
Risk of hematoma
Low molecular weight heparin drugs and MOA
MOA: bind to antithrombin which inactivates factor Xa and Factor IIa
Drugs: Enoxaparin, dalteparin
LMWH BBW, CI, SE
BBW: patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture d/t risk of hematoma and paralysis
CI: History of HIT, active bleed
SE: BLeeding, anemia, injection site reactions, decreased platelets
When should you monitor anti Xa levels when using LMWH?
In pregnancy
Also obesity, low body weight, pediatrics, elderly, or renal insufficiency
LMWH antidote
protamine
What medications are used to break down clots but have a low risk of bleeding?
Fibrinolytics
HIT is an immune mediated reaction that involves which immunoglobulin
IgG
HIT vs HITT
Heparin induced thrombocytopenia
Heparin induced thrombocytopenia + thrombosis
Typical onset of HIT
5-14 days
If a patient is diagnosed with HIT and they are on warfarin, what should you do and why?
D/c warfarin and give vitamin K
Warfarin use with low platelet count has a high correlation with warfarin-induced limb gangrene and necrosis
When can you start warfarin in someone who was diagnosed with HIT?
When platelets have recovered to >150,000
Overlap with non-heparin anticoagulant for at least 5 days until INR is within goal for >24 hours
Apixaban (Eliquis) dosing for
Nonvalvular afib
Treatment of DVT/PE
Nonvalvular afib: 5mg PO BID (2.5mg in certain populations)
Treatment of DVT/PE: 10mg PO BID x 7 days then 5mg PO BID
What to do if patient missed a dose of
Apixiban (Eliquis)
Take immediately on the same day and BID administration should be resumed
Do NOT double up
What to do if patient missed a dose of
Rivaroxaban (Xarelto)
Administer ASAP on same day
If taking BID can double up on a dose - just maintain total daily dose
What to do if patient missed a dose of
Edoxaban (Savaysa)
Take immediately on the same day
Do NOT double up
What to do if patient missed a dose of
Betrixaban (Bevyxxa)
Take immediately on the same day
Do NOT double up
Rivaroxaban dosing for
Nonvalvular afib
Treatment of DVT/PE
Nonvalvular Afib:
- CrCl >50: 20mg daily with dinner
- CrCl 15-50: 15mg daily with dinner
- CrCl <15: avoid use
Treatment of DVT/PE: 15mg PO BID x 21 days then 20mg daily
- CrCl <30: avoid use
Should rivaroxaban be taken with or without food?
Take dose 15mg and greater with food
Edoxaban dosing for
Nonvalvular afib
Treatment of DVT/PE
Nonvalvular Afib - CrCl > 95: do NOT use - CrCl 51-95: 60 mg daily - CrCl 15-50: 30 mg daily - CrCl <15: not recommended Treatment of DVT/PE: 60mg daily starting 5-10 days after parenteral anticoagulation
Oral direct factor Xa inhibitors BBW, CI, warnings, SE
BBW: patients receiving neuraxial anesthesia (epidural or spinal) or undergoing spinal puncture - risk for hematoma and paralysis; increased risk of thrombotic events with premature discontinuation
CI: active pathological bleeding
Warnings: Not recommended with prosthetic heart valves
SE: well tolerated, bleeding
Antidote for apixaban and rivaroxaban
Andexanet alfa (Andexxa)
When to d/c oral direct factor Xa inhibitors for elective surgery
Rivaroxaban, edoxaban: d/c 24 hours prior to elective surgery
Apixaban: d/c 28 hours prior to elective surgery with moderate-high bleeding risk or 24 hours before low bleeding risk
Fondaparinux BBW, CI, SE
BBW: Patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis
CI: severe renal impairment (CrCl < 30 mL/min), active bleed, bacterial endocarditis
SE: bleeding, anemia, local injection site reactions, thrombocytopenia, hypokalemia, hypotension
Fondaparinux antidote
None
Conversion from warfarin to another oral anticoagulant
Stop warfarin and convert to ____ when INR is ____
Rivaroxaban <3
Edoxaban 2.5 or less
Apixaban <2
Dabigatran <2
Conversion from oral Xa inhibitors (apix, edox, and rivaroxaban) to warfarin
Overlap Xa inhibitor with warfarin until INR is therapeutic
Stop Xa inhibitor and start parenteral anticoagulant and warfarin at next scheduled dose
Conversion from dabigatran to warfarin
Start warfarin 1-3 days before stopping dabigatran
What medications are direct thrombin inhibitors?
Dabigatran
Argatroban
Bivalirudin
What to do if patient missed a dose of
Dabigatran (Pradaxa)
Take ASAP unless it is within 6 hours of the next dose
Do NOT double up
Dabigatran (Pradaxa) dosing for
Nonvalvular afib
Treatment of DVT/PE
Nonvalvular afib
150mg BID
CrCl 15-30: 75mg BID
CrCl <15: no recommendations
Treatment of DVT/PE
150mg BID starting 5-10 days after parenteral anticoagulation
CrCl < 30: no recommendation
Dabigatran (Pradaxa) BBW, CI, SE
BBW: Patients receiving neuraxial anesthesia (epidural, spinal) or undergoing spinal puncture are at risk of hematomas and subsequent paralysis; premature d/c increases thrombotic risk
CI: active pathological bleeding, mechanical heart valve
SE: dyspepsia, gastritis-like symptoms, bleeding
Dabigatran (Pradaxa) antidote
idarucizumab (praxbind)
What DOAC needs to be dispensed in it’s original container?
Dabigatran (Pradaxa)
What medications are safe to use in patients with HIT?
argatroban and bialirudin
Warfarin MOA
competitively inhibits vitamin K epoxide reductase (VKORC1) enzyme complex causing depletion of active clotting factors II, VII, IX, and X
What to do if a patient misses a dose of warfarin?
Take ASAP on the same day
Do not double dose the next day
Warfarin BBW, CI, warnings, SE
BBW: major or fatal bleeding
CI: pregnancy (except with mechanical heart valve at high risk of clot), uncontrolled HTN, recent eye surgery or CNS, possible miscarriage
Warnings: tissue necrosis/gangrene, HIT, presence of CYP2C9*2 or *3 alleles and/or polymorphism of VKORC1 gene may increase bleeding risk
SE: bleeding/bruising, purple toe syndrome
What is the typical warfarin INR goal? When should it be higher?
Typical: 2-3
Higher if mechanical mitral valve or 2 mechanical heart valves
Warfarin antidote
Vitamin K (phytonadione)
What warfarin tablet color is associated with each dose?
Please Let Greg Brown Bring Peaches To Your Wedding Pink 1 Lavender 2 Green 2.5 Brown 3 Blue 4 Peach 5 Teal 6 Yellow 7.5 White 10
What medications decrease INR while on warfarin
aprepitant, bosentan, carbamazepine, phenobarbital, phenytoin, primidone, rifambin, licorice, and st. john’s wort
What medications increase INR while on warfarin
amiodarone, azole antifungals, capecitabine, etravirine, fluvastatin, fluvoxamine, macrolide, abx, metronidazole, bactrim
What foods are high in vitamin K?
Broccoli, brussel sprouts, cabbage, spinach, tea (green/black)
Green leafy veggies
What natural supplements increase bleeding risk while on warfarin?
Garlic, ginger, ginkgo, ginsent, glucosamine
Bromelain, don quai, vitamin D, high dose fish oil, willow bark, wintergreen oil
What natural supplements decrease bleeding risk while on warfarin?
Alfalfa, green tea, coenzyme Q10, st john’s wort
Protamine sulfate indication, BBW, SE
Indication: UFH/LMWH reversal
BBW: hypersensitivity
SE: hypotension, bradycardia, flushing, anaphylaxis
Idarucizumab indication, warnings, SE
Indication: dabigatran (Pradaxa) reversal
Warning: thromboembolic risk
SE: HA, low K, delirium, constipation, fever
Andexanet alfa indication, BBW, SE
Indication: apixaban and rivaroxaban reversal
BBW: thromboembolic risks, ischemic events, cardiac arrest, sudden death
SE: injection site reaction, DVT, ischemic stroke, UTI, pneumonia
Vitamin K (phytonadione) indication, BBW, SE
Indication: warfarin reversal
BBW: hypersensitivity reactions (rare)
SE: anaphylaxis, flushing, rash, dizziness
Four factor prothrombin complex concentrate (Kcentra) indication, BBW< CI, warnings, SE
Indication: warfarin reversal
BBW: arterial and venous thromboembolic complications
CI: disseminated intravascular coagulation (DIC) and known HIT
Warnings: made from human blood and may carry risks of transmitting infectious agents
SE: HA, N/V/D, arthralgia, hypotension, low K, thrombotic events
When to use IV vs PO vitamin K to reverse warfarin?
INR <4.5 - skip warfarin dose and monitor
INR 4.5-10 and no bleeding: hold 1-2 doses warfarin and monitor
INR >10 and no bleeding - hold warfarin and give vitamin K
INR at any level and major bleeding 5-10mg IV vitamin K and Kcentra
When to stop warfarin before major surgery
Stop ~5 days before surgery
Can bridge with LMWH or UFH (d/c LMWH 24 hours before surgery and UFH 6 hours before surgery)
Resume warfarin 12-24 hours after surgery
How long should VTE be treated for?
3 months if known cause of VTE
if unknown cause of VTE can treat for longer if not high bleeding risk
What medications are preferred in patients without cancer? With cancer?
Without: dabigatran, rivaroxaban, apixaban, and edoxaban
With: LMWH
Patients with mechanical heart valves and atrial fibrillation/flutter are anticoagulated with what?
Warfarin only because they are high risk
What does CHADSVASc stand for?
CHF HTN Age>/75 years - 2 Diabetes Stroke/TIA prior - 2 Vascular disease (MI, PAD, aortic plaque) Age 65-74 Sex, female
What are the CHADSVASc risk categories and recommended therapies?
Score 0 (M) or 1 (F): no anticoagulation recommended Score 1 (M) or 2 (F): Oral anticoagualtion may be considered Score 2 (M) or 3 (F): Oral anticoagulation recommended; DOAC preferred
What anticoagulant medications are preferred in pregnancy? Which are contraindicated?
Preferred: LMWH (DOC), UFH, pneumatic compression
CI: warfarin (may use during second/third trimester and change back to LWMH close to delivery)
DOACs have not been studied and are not recommended
Which anticoagulant should be kept in the original bottle and not put in a pill organizer?
dabigatran
