Anticoagulation Flashcards
1
Q
Warfarin inhibits…
A
- Factor II
- Factor VII
- Factor IX
- Factor X
2
Q
Direct Xa Inhibitors
A
- RivaroXAban
- ApiXAban
- EdoXAban
3
Q
Indirect Xa Inhibitor
A
Fondaparinux (SQ)
4
Q
Heparins and Where They Work
A
- Unfractionated, UFH (equal Xa and IIa activity)
- LMWH - Enoxaparin, Dalteparin (More Xa than IIa activity)
- Work via antithrombin
5
Q
Direct Thrombin Inhibitors
A
- IV: Argatroban, Bivalirudin
- PO: Dabigatran
6
Q
UFH Dosings
A
- VTE Prophylaxis: 5000u SQ Q8-12H
- VTE Treatment: 80u/kg bolus IV, 18u/kg/hr infusion (continuous, short half life)
- ACS/STEMI Tx: 60u/kg IV bolus, infuse 12u/kg/hr
- TBW for dosing!!!
- HIT antibodies cross react with LMWH
7
Q
UFH Information
A
- SE: HIT (platelets drop >50% from baseline, thrombocytopenia), hyperkalemia, osteoporosis with long-term use
- Monitor: aPTT and anti-Xa level - check Q6H
- aPTT should be between 1.5-2.5 * control
- CAUTION: fatal errors associated with Heparin lock-flushes dosing mix-ups (10x dose. used to keep lines open)
- Antidote: protamine
- Unpredictable anticoagulation response
8
Q
LMWH VTE Dosing
A
- VTE Prophylaxis: 30 mg SQ Q12H or 40 mg QD
- VTE Tx: 1 mg/kg SQ Q12H or 1.5 mg/kg SQ QD (inpatient only, pref. anticoag for cancer pts)
- CrCl < 30: lower dosing option at Q24H
- TBW for dosing!!!
9
Q
LMWH STEMI Dosing
A
- Pts < 75 yo: 30 mg IV bolus + 1 mg/kg SQ dose (then Q12H) Only indication for IV administration
- CrCl < 30: same as above except dose is given QD instead of Q12H OR 1mg/kg SQ QD with no bolus
- Patient’s over >=75 yo don’t get bolus
- TBW for dosing!!!
10
Q
LMWH Information
A
- Boxed warnings: neuraxial anesthesia => hematoma and paralysis risk
- CI: HIT history
- Anti-Xa monitoring only recommended in pregnancy (obtained 4 hours after SQ dose, peak)
- Antidote: protamine
- Don’t expel bubbles from syringe
11
Q
Apixaban Dosing
A
- Nonvalvular Afib (NVAF): 5 mg PO BID
- IF patient is 2 of following: >= 80 yo, BW =< 60 kg, or SCR >=1.5 then 2.5 mg PO BID for Afib
- DVT/PE Tx: 10 mg PO BID x 7 days then 5 mg PO BID (preferred in pts w/o cancer)
12
Q
Rivaroxaban Dosing
A
- Doses >= 15 mg need to be taken with food
- Take Afib doses with evening meals
- DVT/PE Tx: 15 mg PO BID x 21 days then 20 mg PO QD with food
- Avoid use in CrCl < 30
13
Q
Rivaroxaban Missed Doses
A
- If taking 15 mg BID, take two tablets immediately to ensure 30 mg/day, then back to scheduled dosing
- If taking 10/15/20 mg QD: take immediately the same day, otherwise skip
14
Q
Edoxaban
A
- Direct Xa Inhibitor
- Don’t use if CrCl > 95 (reduced efficacy)
- Start after 5-10 days parenteral anticoagulation
15
Q
DOAC Information
A
- Boxed Warning: Neuraxial anesthesia => risk of hematomas/paralysis
- Not recommended for prosthetic heart valves or antiphospholipid syndrome
- Antidote: Andexanet alfa (Andexxa) - for Eliquis and Xarelto
- Avoid taking with bleed risk drugs (SSRIs, SNRIs, NSAIDs, herbals) and CYP3A4i
16
Q
Fondaparinux
A
- Indirect Xa Inhibitor
- Boxed Warning: neuraxial anesthesia => hematoma and paralysis
- CI: severe renal impairment (CrCl < 30)
17
Q
Warfarin to Oral Anticoagulant
A
Stop Warfarin to switch to:
- Rivaroxaban when INR < 3
- Edoxaban when INR =< 2.5
- Apixaban when INR < 2
- Dabigatran when INR < 2
18
Q
Oral Anticoagulants to Warfarin
A
- Overlap Xa with warfarin until INR is therapeutic (for 5 days AND INR >=2 for at least 24 hours)
- Stop Xa inhibitor and warfarin at next dose
19
Q
Dabigatran to Warfarin
A
- Start warfarin 1-3 days before stopping dabigatran
- Determined by renal function
20
Q
Dabigatran Dosing
A
- Direct Thrombin Inhibitor (oral)
- Dispense in original container and discard 4 mo after opening
- Swallow capsules whole, NO NG TUBE
- Take missed dose immediately unless next dose is within 6 hours, then skip (don’t double)
21
Q
Dabigatran Information
A
- Boxed Warning: Neuraxial anesthesia => hematoma and paralysis
- CI: mechanical, prosthetic heart valves
- SE: Dyspepsia, gastritis-like sxs, bleeding (including GI)
- No monitoring required
- Antidote: idarucizumab (Praxbind)
22
Q
IV Direct Thrombin Inhibitors
A
- Argatroban and Bivalirudin (Angiomax)
- Used in patients at risk for HIT
- No cross-reaction with HIT-antibodies
- No antidote
23
Q
Warfarin Dosing
A
- 10 mg QD for 2 days in health outpatient then adjust per INR
- Lower dose (=<5 mg) for elderly, malnourished, CYP inhibitors, liver disease, HF, or high risk bleeders
- S-enantiomer is 2.7-3.8x more potent
- Don’t double doses if missed, take immediately same day or skip
24
Q
Warfarin Information
A
- CI: Preggo UNLESS mechanical heart valve
- Warning: tissue necrosis/gangrene, HIT, presence of CYP2C9 2/3 alleles or VKORC1 gene
- SE: Purple toe syndrome, bleed, bruise, necrosis
- Higher INR goal (2.5-3.5) for mechanical mitral or 2+ mechanical valve patients
- Antidote: Vitamin K
25
Q
CYP2C9 Inducers
A
Decrease INR
- Rifampin (large decrease)
- PS PORCS
- Aprepitant
- Bosentant
26
Q
CYP2C9 Inhibitors
A
Increase INR (MAT)
- M: Metronidazole and macrolides
- A: Amiodarone and azoles (Fluconazole)
- T: TMP/SMX
27
Q
Warfarin DDI
A
- NSAIDs, antiplatelet agents (clopidogrel), other anticoagulants, and SSRIs/SNRIs increase bleeding risk but not INR
- Estrogen and SERMs increase clotting risk
28
Q
Natural Medicines + Warfarin
A
INCREASE bleeding risk
- 5 Gs (garlic, ginseng, ginkgo, ginger, and glucosamine)
- Vitamine E
- Dong quai
- Fish oils (high dose)
- Willow bark (natural salicylate)
- Wintergreen oil
DECREASES Warfarin Efficacy
-St. John’s Wort
29
Q
Protamine
A
- Antidote for UFH/LMWH
- 1mg of protamine reverses ~100u of heparin
- Reverse amount given in last 2-2.5 hours
- Max dose: 50 mg
- 1:1 for LMWH, only reverse last 8 hours
30
Q
Kcentra
A
-Four Factor Prothrombin Contains: -Factor II -Factor VII -Factor IX -Factor X -Protein C -Protein S
-Administer with Vitamin K (usually IV) for warfarin reversal with major bleeding
31
Q
Phytonadione
A
- Vitamin K, warfarin antidote
- Given IV or PO (1-10 mg)
- Boxed warning: hypersensitivity (anaphylaxis)
- Requires light protection
- SQ has variable absorption and IM has risk of hematoma
- Don’t reverse until INR > 10 and/or bleed (w/o bleed use oral)
32
Q
HIT
A
- Diagnosis: PLT drop >50%
- IgG reaction
- Risk for UFH and LMWH (cross-reactive between meds)
33
Q
Praxbind
A
- Idarucizumab
- Antidote for Pradaxa (dabigatran)
34
Q
Angiomax
A
- Bivalidurin
- Injectable direct thrombin inhibitor (IV)
- Mainly used/seen in cardiac/cath. labs
35
Q
Warfarin Colors
A
Please Let Greg Brown Bring Peaches To Your Wedding: P: Pink - 1 mg L: Lavender - 2 mg G: Green - 2.5 mg B: Brown - 3 mg B: Blue - 4 mg P: Peach - 5 mg T: Teal - 6 mg Y: Yellow - 7.5 mg W: White - 10 mg
36
Q
Andexxa
A
- Andexamet alfa
- Antidote for xarelto and rivaroxaban (ONLY)
