Anticoagulation Flashcards
Coag Cascade
Warfarin inhibits: 2, 7, 9, 10
Riva/Apix/Edoxa inhibits: Xa (direct)
Fondaparinux inhibits: Xa (indirect)
Arg/Bival/Dabi inhibits: Thrombin 2a
UFH: equal anti-Xa and anti-2a activity
LMWH: more anti-Xa than anti-2a activity
DOACs vs Warfarin
DOACs:
-Fewer DDIs, less or comparable bleeding, and shorter onset/duration
-Dosing based on indication and kidney/liver function, no monitoring
DOACs preferred in stroke prevention in AF and for VTE treatment
-BUT mod-sev mitral stenosis, triple + antiphospholipid syndrome, or mechanical heart valve = warfarin
Bleeding Types for High Alert Medications (all AC)
-Epistaxis (nose bleed)
-Gums
-Bruising
-Hematoma
-Hematemesis (blood in GI tract, esophageal, stomach, duodenal)
-Hematuria (blood in urine)
-Blood in anus
*can be bright red or tarry/black (the farther the bleeding site from the anus - the darker the stool)
Unfractionated Heparin: Dosing
PPX VTE
= 5000 units SC Q8-12h
TX VTE
= 80 u/kg IV bolus, 18 u/kg/hr infusion
TX ACS/STEMI
= 60 u/kg IV bolus, 12 u/kg/hr infusion
USE TOTAL BODY WEIGHT FOR DOSING
UFH: CI/AE/Monitoring
CI:
-Active bleed
-Severe thrombocytopenia
-HIT history
AE: bleeding, HIT, thrombocytopenia, hyperkalemia, osteoporosis, alopecia
Monitoring: aPTT or anti-Xa level
-Check 6 hr after initiation and every 6 hr until therapeutic, then every 24 hr and with every dosage change (monitoring not required for SC PPX)
-aPTT thera range is 1.5-2.5x control
-Anti-Xa thera range is 0.3-0.7
-PLT, Hgb at baseline/daily (>50% drop in PLTs = possible HIT)
Antidote: protamine
Hep lock-flushes (HepFlush) are only used to keep IV lines open (potential for fatal errors)
LMWH (Enoxaparin, Lovenox): Dosing
PPX VTE
= 30 mg SC Q12h or 40 mg SC QD
TX VTE
= 1 mg/kg SC Q12h or 1.5 mg/kg SC QD (1.5 is only for inpatient VTE tx)
-CrCl < 30: 1 mg/kg SC QD
TX STEMI in age < 75
= 30 mg IV bolus plus a 1 mg/kg SC dose followed by 1 mg/kg SC Q12h
*Max 100 mg for the first 2 SC doses only
-CrCl < 30: 30 mg IV bolus plus a 1 mg/kg SC dose followed by 1 mg/kg SC QD
TX STEMI in age 75+
= 0.75 mg/kg SC Q12h (no bolus - max 75 mg for the first two SC doses only)
-CrCl < 30: 1 mg/kg SC daily (no bolus)
USE TOTAL BODY WEIGHT FOR DOSING
LMWH (Enoxaparin/Dalteparin): CI/AE/Monitoring
CI: HIT hx, active bleed, hypersensitivity to pork
AE: bleeding, anemia, injections site rxn, decrease PLTs (HIT, thrombocytopenia)
Monitoring: not required (more predictable)
-Anti-Xa rec in pregnancy, renal, obesity, low body weight
*Peak Anti-Xa levels 4 hr post SC dose
Antidote: protamine
Don’t expel air bubbles from syringe (loss of drug), store at room temperature
PLOR to be HAPER
HIT
4 T Score
-Thrombocytopenia (PLTs drop >50%)
-Timing (5-10 days within heparin or a few hours if has gotten heparin in past 3 months)
-Thrombosis
-Other: ruling out other causes
Heparin PF4 antibody enzyme immunosorbent assay (ELISA) to confirm HIT
Management:
-Stop heparin and LMWH
-Use argatroban/bivalrubin (bival preferred in cardiac surgery/PCI)
-No warfarin until PLTs 150k+ and overlap with non-heparin AC (Arg can increase INR)
Apixaban (Eliquis): Dosing
Nonvalvular AF (Stoke PPX)
= 5 mg BID
-If pt has 2 of 80+/<60kg/Scr 1.5+ then give 2.5 mg BID
TX DVT/PE
= 10 mg BID x 7 days then 5 mg BID
-Extended phase (>6mo): 2.5 mg BID
PPX DVT/PE (knee/hip replacement)
= 2.5 mg BID for 12 days after knee and 35 days after hip (first dose 12-24 hr after surgery)
Rivaroxaban (Xarelto): Dosing
Doses 15+ mg must be taken with food (10 mg without regard to food)
Nonvalvular AF (Stoke PPX)
-CrCl > 50: 20 mg QD with meal
-CrCl 15-50: 15 mg QD with meal
-CrCl < 15: 15 mg QD with meal per manufacturer (limited data)
TX DVT/PE
= 15 mg BID x 21 days then 20 mg QD with food
-Extended phase (>6mo): 10 mg QD
-CrCl 15-30: caution
-CrCl < 15: avoid use
PPX DVT/PE (knee/hip replacement)
= 10 mg QD for 12 days (knee) and 35 days (hip) or 31-39 days (acutely ill pts)
-First dose 6-10 hours after surgery
-CrCl 15-30: caution
-CrCl < 15: avoid use
Edoxaban (Savaysa): Dosing
Nonvalvular AF (Stroke PPX)
-CrCl > 95: do not use
-CrCl 51-95: 60 mg QD
-CrCl 15-50: 30 mg QD
-CrCl < 15: not recommended
TX DVT/PE
= 60 mg QD, start after 5-10 days of parenteral AC
-CrCl 15-50, ≤ 60 kg or on certain P-gp inhibitors: 30 mg QD
-CrCl < 15: not recommended
Factor Xa (Apix/Riva/Edox): CI/AE/Notes
CI: pathological bleeding
-Not recommended with prosthetic heart valves or tripie + antiphospholioid syndrome
No monitoring required
Antidote for apix/riva: Andexxa (andexanet alfa)
All can be crushed (apple sauce or suspended in water)
-Apixaban only: mixed in water/D5W/apple juice
Elective Surgery:
-Riva/edox: stop 24 h prior
-Apix: stop 48 h prior (mod-high bleed risk) or 24 h prior (low bleed risk)
P ARA CAM E = RE24 A4824
Fondaparinux (Arixtra): CI/AE/Notes
CI: severe renal impairment
-CrCl < 30
AE: bleeding, anemia, injection site rxn
No antidote, do not expel air bubble from syringe
BBW for Factor Xa (Apixaban, Rivaroxaban, Edoxaban, Fondaparinux)
FARE BBW:
Pts receiving neuraxial anesthesia (epidural/spinal) are at risk of hematomas and paralysis
DDIs for Factor Xa (Apixaban, Rivaroxaban, Edoxaban, Fondaparinux, Pradaxa)
Apixaban
-Dual 3A4 and PGP: carbamazepine, phenytoin, rifampin, SJW
Rivaroxaban
-Same + azole, ritonavir, conivaptan
-No Cobicistat, Genvoya, Stribild
Conversion Between Anticoagulants
Wafarin to other AC: READ
*Stop warfarin and start…
-Riva when INR < 3
-Edox when INR ≤ 2.5
-Apixa when INR < 2
-Dabi when INR < 2
Apix/Edox/Riva to Warfarin:
-Stop Xa and start parenteral AC and warfarin at next scheduled dose
Dabi to Warfarin:
-Start warfarin 1-3 days before stopping dabigatran
Dabigatran (Pradaxa): Dosing
Nonvalvular AF (Stroke PPX)
= 150 mg BID
-CrCl 15-30: 75 mg BID
-CrCl < 15: avoid use
TX DVT/PE
= 150 mg BID, start after 5-10 days of parenteral AC
-CrCl < 30: avoid use
Dabigatran (Pradaxa): CI/AE/Notes
CI:
-Active bleeding
-Mechanical prosthetic heart valves
AE:
-Dyspepsia
-Gastritis like sx
-Bleeding (GI)
Antidote: idarucizumab (Praxbind)
Dispense in OG container and discard after 4 months of opening
No crush/chew, no NG tube
BIG OD 4
Argatroban and Bivalrudin (Angiomax)
-AE: bleeding, anemia
-Monitoring: aPTT, PLT, Hgb, renal
-Used for active HIT or HIT hx
-No antidote
-Arg can inc INR (caution if starting warfarin)
-Bival preferred in cardiac surg/PCI
Warfarin: Dosing
Healthy outpatients:
= ≤ 10 mg QD for first 2 days, then adjust dose per INR
Overlap parenteral AC for at least 5 days and until INR >2 for at least 24 h
Lower doses (≤ 5 mg) for elderly, malnourished, taking drugs which can increase warfarin levels, liver disease, heart failure, or high risk of bleeding (MEDLHB)
Take at SAME TIME each day
Warfarin: BBW/CI/AE/GOALS
BBW: fatal bleeding
CI: pregnancy (unless mech valve)
-CI as mono therapy in initial tx of active HIT
W: CYP2C9 *2 or *3 alleles or VKORC1 gene (inc bleeding)
AE:
-Necrosis, gangrene
-Purple toe syndrome
-Bleeding, bruising
Goal INR 2-3 (target 2.5) for VTE/AF/APS
Goal INR 2.5-3.5 (target 3) for mech mitral valve, 2 mech valves or mech aortic valve with 1 additional risk (prior DVT/AF/hypercoag stat)
Monitor INR after 2-3 initial doses then every 4-12 weeks
Antidote: vitamin K
Warfarin: DDIs
-Carbamazepine
-Phenobarbital, Phenytoin
-Rifampin
-SJW
-Amiodarone (dec by 30-50%)
-Azoles
-Metronidazole
-Bactrim
-Estrogen (SERMs)
CPR on my BAE SAM
Warfarin: Food/Supplements
Inc bleeding risk
-Chondroitin, high doses of fish oils, garlic, ginger, ginkgo, ginseng, glucosamine, willow bark
Dec warfarin efficacy
-Green tea, COQ10, SJW
Stay consistent with the amount of vitamin K in the diet (spinach, broccoli, Brussel sprouts, collard greens, kale)
Warfarin: Tablet Colors
Pink 1 mg
Lavender 2 mg
Green 2.5 mg
Brown/Tan 3 mg
Blue 4 mg
Peach 5 mg
Teal 6 mg
Yellow 7.5 mg
White 10 mg
Pls Let Greg Brown Bring Peaches To Your Wedding
