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