34. Anticoagulation Flashcards
T/F: Anticoagulants break down clots
False - they prevent blood clots from forming and keeping existing clots from getting bigger but do not break down clots
What can cause blood clots for form?
Blood vessel injury, blood stasis (stopping/slowing of blood flow) and prothrombotic conditions
What part of the coagulation cascade do UFH/LMWH (enoxaparin, dalteparin) work on?
Xa and thrombin IIa via antithrombin
UFH: equal anti-Xa and anti-thrombin IIa activity
LMWH: most anti-Xa activity than IIa
What part of the coagulation cascade does warfarin work on?
Inhibits factors II, VII, IX, and X
What part of the coagulation cascade do rivaroxaban, apixaban, edoxaban work on?
Xa (direct inhibitor)
What part of the coagulation cascade does argatroban (IV), bivalirudin (IV), dabigatran (PO) work on?
Thrombin IIa
What part of the coagulation cascade does fondaparinux work on?
Xa (indirect inhibitor) via antithrombin
DOACs are generally preferred for stroke prevention in Afib but if _______, use warfarin
mod-severe mitral stenosis or mechanical heart valve
DOACs are generally preferred for VTE treatment but if _____, use warfarin
antiphospholipid syndrome or mechanical heart valve
Compare DOACs vs warfarin in terms of DDIs, bleeding risk, and duration of action
DOACs have less DDIs, less or comparable bleeding risk, and shorter duration of action compared to warfarin
_____ do not cross-react with heparin-induced thrombocytopenia (HIT) antibodies
IV direct thrombin inhibitors (argatroban, bivalirudin)
T/F: all anticoagulants can cause significant bleeding and are classified as “high-alert” meds by ISMP
True
An acute drop in ___ (e.g. ≥ 2g/dL) could signify that bleeding is occurring (visible or not)
Hgb
UFH MOA
binds to antithrombin and accelerates its ability to inactivate thrombin (factor IIa) and factor Xa and prevents conversion of fibrinogen to fibrin
UFH dosing for VTE ppx
5000 units SC Q8-12H
UFH dosing for VTE treatment
80 units/kg IV bolus; 18 units/kg/hr infusion
Note: use TBW for dosing
UFH dosing for ACS/STEMI
60 units/kg IV bolus; 12 units/kg/hr infusion
Note: use TBW for dosing
Side effects of UFH
bleeding, thrombocytopenia, HIT, hyperkalemia, osteoporosis (long-term use), alopecia
Monitoring for UFH
aPPTT or anti-Xa level - check 6 hrs after initiation and q6h after therapeutic
aPPT therapeutic range is 1.5-2.5x control (depends on institution)
Platelets, Hgb, Hct at baseline and daily (decrease in platelets >50% from baseline suggests possible HIT)
Note: aPTT and anti-Xa monitoring not required for SC (VTE ppx)
Antidote of UFH
Protamine
Why is UFH continuous IV infusions common for treating VTE and ACS?
Short half-life (1.5hrs)
Why should UFH not be given IM?
hematoma risk
Heaprin lock-flushes (HepFlush) are only used to ___. Fatal errors, especially in neonates have occured when incorrect heparin strength (higher conc) was chosen.
Heparin injection 10,000 units/mL vs flushes 10 or 100 units/mL.
keep IV lines open
LMWH MOA
bind to antithrombin and accelerate ability to inactivate factor Xa and IIa
Anti-factor Xa activity»_space;» anti-factor IIa activity