Anticoagulation Flashcards
Which factors does warfarin inhibit
2, 7, 9, 10
Which are the direct xa inhibitors?
DOACS
What does fondaparinux inhibit?
Antithrombin which indirectly inhibits xa
What does UFH inhibit
antithrombin which then inactivates thrombin (factor 2a) and 10a
what does LMWH inhibit
smaller so more xa than antithrombin but both
What are the direct thrombin inhibitors?
argatroban, bivalirudin, dabigatran
Heparin VTE tx and prophylaxis dosing
Prophylaxis: 5000 units q8-12h
Treatment: 80 units/kg bolus then 18 units/kg/hr
Heparin ACS/STEMI dosing
lower than vte; 60 units/kg IV bolus then 12 units/kg/hr
Which meds are dosed via IBW if obese
acyclovir, aminophylline, levothyroxine
Which meds are does via IBW regardless of obesity
theophylline
Which meds are does via adjusted body weight if obese
Aminoglycosides
What is HIT defined as?
Unexplained drop in platelet 50% from baseline
What is the warfarin tablet color pneumonic
Please - pink 1 Let - Lavender 2 Greg- Green 2.5 Brown - Brown/Tan 3 Bring - Blue - 4 Peaches - Peach 5 To - Teal - 6 Your - Yellow 7.5 Wedding - White 10
Starting doses for warfarin
Healthy give 10mg for 1st 2 days, in elderly start less then 5
What is used to reverse UFH/LMWH and dosing
protamine.
- UFH: 1 mg reverses 100 units with a max of 50mg. Reverse the amount given in the last 2 hours.
- LMWH - 1 mg per 1 mg of lovenox
dabigitran reversal agent
praxbind/Idrucizumab
Apixaban and rivaraxoban reversal agent
andexanet alpha/Andexxa
Warfarin reversal
vitk or phytonadione (Mephyton), Kcentra (four factor prothrombin complex concentrate, novosevenRT/Factor VIIa recombinant
CHA2DS2VASC meaning
C- CHF H - HTN A - Age > 75 --2 D - Diabetes S2 - Stroke/TIA -2 V - Vascular Disease A - Age 65-74 S - Sex = female
CHADS2 interpretatioin
No anticoag recomended if 0 in males or 1 in females. Maybe give anticoag if 1 in males or 2 in females. If greater than that for sure give oral coag.
What anti coag can you give in pregnancy
LMWH over UFH
Lovenox generic and MOA
Enoxaparin
- low molecular weight heparin
- binds to Antithrombin which inactivates xa and IIa but prefers xa
eliquis
apixaban
xarelto
rivaroxaban
apixaban dosing
afib: 5mg bid UNLESS older than 80, BW <60kg, or SCR >1.5 then half dose
DVT tx: 10mg po bid x 7 then 5mg po bID
Rivaroxaben dosing
take with food, if for afib with evening meal
DVT tx: 15mg PO BID x 21, then 20mg PO daily
Which DOACS have renal function contraindications?
Rivaroxaban: If CrCL < 30 then avoid use
Edoxaban: If CrCL <95 then avoid use
Heparin monitoring and frequency of labs and interpretation of monitoring labs
aptt or antixa 6 hours after initiation then every 6 hours until therapeutic
aptt is 1.5 - 2.5 control
What to stop if HIT occurs
warfarin, all heparins
what platelet count may you resume warfarin if HIT occurs?
> 150,000
What is a good choice for HIT?
Argibotran, Bivalirudin
direct thrombin inhibitors
Pradaxa
dabigitran
Angiomax
Bivalirudin
What should be used in prosthetic heart valve
warfarin
Which is the SUBQ 10a inhibitor
Fondaparinux
Dabigitran Side effects
Dyspepsia, gastritis like symptoms
dabigatran storage
original container, must use within 4 months
dabigitran administration
1) take within how many hours of next dose
2) how long after iv anticoag
3) can you crush?
must take within 6 hours of next scheduled dose, start 5-10 days after parenteral (IV) anticog, swallow capsules whole no NG tube
warfarin contraindications and warnings
contraindications: Pregnancy (unless mechanical heart valve)
warnings: tissue necrosis/gangrene
3a4 inducers
PS PORCS
phenytoin, smoking, phenobarbital, oxcarbazepine/triptal, rifampin, carbamexapine/tegratol, st. john’s wort
3a4 inhibitors
PACMAN G
PI, azoles, cyclosporine/neoral, cimetidine, cobistat, macrolides (clarithromycin and arithromycin), amiodarone, nondhp CCB (diltiazem and verapamil)
CYP 1A2 substrate
warfarin R (also 3a4), theophylline
CYP 2c9 substrate
warfarin s
important c29 inducer
rifampin (pretty much PSPORCS works here too)
Important 2c9 inhibitors
M - Metranidazole, macrolides
A - Amiodarone, Azoles
T - TMP/SMX
apixaban and rivaroxaban are substrates of what
pgp and cyp3a4
coumadin
warfarin (1/2)
Jantoven
Warfarin (2/2)
what drug to drop warfarin dose
amiodarone, decrease dose by 30-50%
How long do you bridge warfarin for
5 days and then until inr >2 for 24 hours
Once INR is stable how often do you test?
every 12 weeks
phytodione
vit k
mephyton
vitamin k or phytonadione
vitamin k boxed warning and side effects
hypersensitivity reactions, possible anaphylaxis
If the INR is <4.5 but above therapeutic range what do you do
skip or reduce dose and monitor
If INR is between 4.5 and 10 but there is no bleeding what do you do
give oral vitamin k and hold
If patient is bleeding regardless of INR
give slow IV warfarin and PCC
How long to stop warfarin before surgery and after
5 days before, 12-24 hours after, may bridge
how long to treat for VTE
3 months if caused by any of the reversable risk factors
preferred tx in cancer patients
LMWH
If someone has had afib for more than 48 hours give anticoag for how long before and after cardioversion
3 weeks prior to, 4 weeks after while in NSR