Anticoagulation Flashcards
why DOAC over warfarin
- less DDI, less or comparable bleeding, shorter duration of action compared to warfarin
- DOAC dosed based on indication and kidney/liver function, not INR
- DOAC preferred for stroke prevention in AF,
—-> but if moderate to severe mitral stenosis or a mechanical heart valve, use warfarin - DOAC for VTE tx
—-> unless pt has antiphospholipid syndrome use warfarin
antithrombin (AT)
body’s natural anticoagulants. it inactivates thrombin (factor IIa) and other proteases (like factor Xa).
UFH, LMWH< fonda[aromix bind to AT, cause conformational change which increases AT activity by 1,000- fold.
LMWH inhibits factors Xa more than UFH.
Fondaparinux binds to AT resulting in selective inhibition of factor Xa
inhibiting factor Xa directly
apixaban (eliquis)
rivaroxaban (xarelto)
Direct thrombin inhibitors
IV DTIs (e.g. agratroban) are great, do not cross-react with HIT antibodies. Dabigatran is oral DTI
UFH
- fatal med errors can occur, verify concentration,
- check anti-Xa level every 6 hrs , until therapeutic
- decrease in platelets >50% from baseline suggest possible HIT
- HIT antibodies have cross-sensitivity with LMWH
- heparin lock-flushes (HepFlush) are used to keep IV lines open
- hyperkalemia
-monitor hematocrit, hemoglobin, aPTT, and platelets
- antidote: protamine
Enoxaparin
Leovenox
- dose adjustment after <30….
- box warning: neuraxial anesthesia (epidural).. or spinal puncture are at risk for hematomas and subsequent paralysis
- does not require monitoring
- antidote: protamine
- do not expel air from syringe prior to injection…90% angle, abdomen 5cm/2” from umbilicus
- keep in mind it does not require monitoring but extreme body weight (high or low), renal clearance issues, and prego will need monitoring cause of altered pharmacokinetics
Management of HIT
- stop heparin and LMWH
- warfarin should be d/c and vitamin k started
- for immediate tx use non-heparin anticoagulant (e.g. argatroban)
- do not start warfarin until platelet received >150,000, warfarin at a lower dose- 5mg max, overlap with non-heparin anticoagulant for 5 days min, until INR within range for 24 hrs. keep in mind argatroban can increase INR,
- if urgent cardiac surgery such as PCI, bivalirudin preferred
Apixaban
Eliquis
nonvalvular AF 5mg BID
DVT/PE 10mgBID x7days, then 5mgBID
- not recommended in prosthetic heart vales or antiphospholipid syndrome
- antidont andexanet alfa
- can be crushed, mixed in water, DW or apple juice…. put on apple sauce for suspended in water for NG tube too.
-neuraxial anesthesia (epidural).. or spinal puncture are at risk for hematomas and subsequent paralysis
Rivaroxaban
Xarelto
nonvalvular AF (stroke prophylaxis)
- CrCl >50 20mg w/ evening meals
- CrCl 15-50 15mg w/eveing meals
- CrCL <15 avoid use
DVT/PE
- 15mg BID, then 20daily
- CrCl< 30 avoid use
- put on apple sauce for suspended in water for NG tube
- not recommended in prosthetic heart vales or antiphospholipid syndrome
- antidont andexanet alfa
- neuraxial anesthesia (epidural).. or spinal puncture are at risk for hematomas and subsequent paralysis
Edoxaban
Savaysa
- reduced efficacy in nonvalvular AF of pt CrCL >95- do not use
- put on apple sauce for suspended in water for NG tube
- neuraxial anesthesia (epidural).. or spinal puncture are at risk for hematomas and subsequent paralysis
Fondaparinux
Arixtra
- contra in renal <30 CrCl
- neuraxial anesthesia (epidural).. or spinal puncture are at risk for hematomas and subsequent paralysis
Conversion between anticoagulants
from warfarin to oral anticoagulants
stop warfarin and convert to:
Rivaroxaban INR <3
Edoxaban INR <2.5
Abixaban INR <2
Dabigatran INR <2
READ
Conversion between anticoagulants
from oral Xa anticoagulants to warfarin
stop Xa inhibitors, start parental anticoagulants and warfarin at next scheduled dose
Endoxaban only: refer to package insert
Conversion between anticoagulants
from dabigatran to warfarin
start warfarin 1-3 days before stopping dabigatran (determine renal function… and refer to package insert)
Dabigatran
Paradaxa
- oral direct thrombin inhibitor
- neuraxial anesthesia (epidural).. or spinal puncture are at risk for hematomas and subsequent paralysis
- contra in pt with mechanical prosthetic heart valve
- antidote: idarucizumab (praxbind)
- swallow capsules do not admin by NG tube
- missed dose take immediately unless within 6 hours of next dose
argatroban
IV direct thrombin inhibitors
- safe with HIT
Bivalirudin
angiomax
- IV direct thrombin inhibitors
- safe with HIT
- use this if undergoing PCO in pt with HIT risk
-
Warfarin
Coumadin, Jantoven
- do not double the dose or try to make up for the missed dose..
- contra prego unless pt w/ mechanical heart valves
- contra in tissue necrosis/gangrene, HIT
- highly protein bound. pt with hypoalbumin will have issues…
- presence of CYP2C9*2 or *3 and/or VKORC1 polymorphism gene may increase bleeding risk
- antidote: vitamin K
Warfarin INR goal
INR 2-3: most indications (VTE, AF, bioprosthetic mitral valve, mechanical aortic valve, antiphospholipid syndrome)
INR 2.5-3.5: high-risk indications (mechanical mitral valve or 2 mechanical heart valves)
warfarin CYP2C9 inducers
warfarin is a major substrate of CYP2C9, inducers decrease INR (includes carbamazepine, phenobarbital, phenytoin, st johns’s wart, rifampin, aprepitant, bosentan, primidone, licorice)
warfarin CYP2C9 inhibitors
amiodarone, azole antifungals, capecitabine, cimentidine, fluvastatin, fluvoxamine, metronidazole, TMP/SMX, zariflukast, tamoxifen, tigecycline
when starting amiodarone, decrease the dose of warfarin by 30-50%
general increased bleed risk with
NSAID, SSRIs, SNRIs
increased colting risk with estrogen, SERMs
supplements and warfarin
- increased bleed risk with “the 5 G’s” (garlic, ginger, ginkgo, ginseng, glucosamine) dong quai, vitamin E, fish oils @high dose, willow bark, wintergreen oil
- decreased effectiveness: green tea, coq10, st. john’s wort, alfalfa
foods w/ high vitamin K: spinach, broccoli, brussle sprouts, cabbage, beef liver, Kale
Warfarin tablet color
Pink 1mg
Lavender 2 mg
Green 2.5 mg
Brown/tan 3 mg
Blue 4 mg
Peach 5 mg
Teal 6 mg
Yellow 7.5 mg
White 10 mg
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