Ex3 Anticoagulants Flashcards
Big offender in bleeding disorders
herbals: garlic, fish oil, ginko
Disorders of Hemostasis: definition
increased risk of bleeding
Prothrombotic states: definition
increased risk for clotting
HIT
prothrombotic state
antiphospholipid antibody syndrome
prothrombotic state
DIC
prothrombotic state AND disorder of hemostasis
Liver disease
prothrombotic state AND
disorder of hemostasis
Hemophilias
disorder of hemostasis
Von Wilibrand disease
disorder of hemostasis
Factor 8 low
Vitamin K dependent clotting factors
Factors 2, 7, 9, 10
Vitamin K deficiency
disorder of hemostasis
Heparin MOA
Binds to antithrombin III
–>inhibits fxn factors
LMWH differs from UFH
More specific for inhibition of Xa
Renal excretion
UFH differs from LMWH
quick on, quick off, metabolized via endothelium
T/F: heparins & warfarin are dialyzable
False
UFH advantages
short half life, renal dysfxn does not impact clearance, antidote available
UFH disadvantages
frequent lab monitoring, HIT
LMWH advantages
no lab monitoring needed
LMWH disadvantages
Cannot be fully reversed
Renal elimination
Tx for HIT
direct thrombin inhibitors
Bivalrudin/Argatroban
aPTT is effected by
UFH
not affected by LMWH
Lab monitoring used in CABG
ACT
Anti-factor Xa Lab Test
- both LMWH/UFH
- most often for LMWH
- UFH: used for heparin resistance
DOC: UFH reversal
protamine
Protamine contraindications
-fish allergy
Protamine adverse effects
- Anaphylaxis (fish allergy, vasectomy, pt on NPH)
- acute pulm vasoconstriction, hypotension, bradycardia
- slow infusion
Protamine dose
1 mg protamine reverses 100 units UFH IV
Protamine dose based on
UFH over past 2-3 hours
Max protamine
50 mg in 10 minutes
Reversal agent LMWH
None specific to LMWH
-protamine partially effective
Dosage for LMWH reversal
- 1mg protamine per 1 mg enoxaparin given w/in last 8h
- Max dose 50mg
After max dose protamine
0.5 mg for every 1mg (LMWH) and 100 units (UFH) if bleeding continues
reason Recombinant factor VIIa not used often
high risk for thrombosis
4F-PCC contraindicated
- HIT
- Heparin allergy
(only factor product +heparin)
Vitamin K antagonist
Warfarin
Warfarin MOA
Inhibits activation of Vit.K dependent clotting factors (Factors 2, 7, 9, 10, Protein C+S)
Onset Warfarin
Full anticoagulation effect not achieved until 4 days
What is needed during initiation of warfarin?
LMWH/UFH d/t hyper-coagulable state
reversal of warfarin
elective/nonurgent surgery
oral/iv vitaminK
reversal of warfarin
urgent surgery
4 factor PCC + IV vitamin K
reversal of warfarin
minor bleeding
iv vitamin k
reversal of warfarin
major bleeding
4 factor PCC + IV vitamin k
risk of PCC
increased risk of thromboembolic event
unique aspect of dabigatran
dialyzable (57% over 4h)
Bivalrudin/argatroban reversal
Supportive care/time
Dabigatran reversal
- activated charcoal if w/in 2 hours
- Idarucizumab direct reversal
no role for reversal if presentation ________ after cessation of therapy
3-5 half lives
No role for ______ to reverse DTIs
plasma
advantages of NOACs
no lab monitoring
disadvantages of NOACs
not indicated for mechanical valve
Direct factor Xa inhibitors - which are dialyzable?
Apixaban (minimal)
No - Rivaroxaban, Edoxaban
Standard monitoring for NOACs
-thrombin time
-CBC w/ differential
-renal/hepatic function
(dabi - only renal fxn)
S/S OD dabigatran
aPTT > 2.5x control
Reversal of rivaroxaban, apixaban
Andexxa
- w/in 2h: active charcoal
- bolus then infusion
injectable Xa inhibitor
Fondaparinux
-no direct reverse (only activated PCC)
What should you do prior to neuraxial anesthesia?
Check Azra guidelines
avoid neuraxial anesthesia in patients taking
fibrinolytics/thrombolytics
length of time to d/c heparin prior to neuraxial anesthesia
4-6h
ideal situation if pt on anticoagulants & needs to go to OR
bridge with short acting parenteral therapy (UFH/LMWH)
Warfarin should be held _____ prior to OR
5 days
LMWH should be held _____ prior to OR
24h
UFH should be held _____ prior to OR
4h
antiplatelet agents
- clopidogrel, prasugrel, ticagrelor, cangrelor
- aspirin, NSAIDs
- dipyridamole
Prodrugs
Clopidogrel
Prasugrel
inhibitors (antifungal/sedatives/antiepileptics) with clopidogrel
prevents breakdown of drug to active form
*same w/ prasugrel
Percent platelet inhibition
aspirin - 20
clopidogrel - 40
prasugrel - 70
ticagrelor - 95
Reversible platelet binding
Ticagrelor
IV antiplatelet agent
cangrelor
continuous infusion
metabolism of cangrelor
metabolized by dephosphorylation - restores platelets QUICKLY
- independent of organ dysfunction
- not dialyzable
AE desmopressin
tachyphylaxis
Antiplatelet agents in high risk pts before surgery
Cangrelor or glycoprotein IIb/IIIa inhibitors
Glycoprotein IIb/IIIa inhibitors
tirofiban
eptifibatide
antifibrinolytic agents
aminocaproic acid
tranexamic acid
risk of tranexamic acid
seizures d/t possible block of GABA receptors