Anticoagulation Flashcards
Heparin MOA
Potentiates antithrombin → decreased transformation of prothrombin to thrombin
Heparin Route of Administration
SQ (prophylaxis) or IV Continuous Infusion (treatment)
Heparin Half-Life
1-2 hours (IV)
Heparin Monitoring (efficacy)
Either Anti-Xa levels (~0.3-0.7 units/mL) or aPTT levels (ranges vary per lab) need to be within therapeutic range
Low molecular weight hearpin (LMWH) MOA
Potentiates antithrombin → decreased transformation of prothrombin to thrombin AND inactivates factor Xa
LMWH Route of Administration
SQ (rarely can be given IV)
LMWH Half-Life
~12 hours
LMWH Dose Adjustments
CrCl < 30 mL/min
LMWH Efficacy Monitoring
Anti-Xa levels only in specific populations - obese, renal dysfunction, pregnant
List the Direct acting oral anticoagulants
Apixaban (Eliquis), Rivaroxaban (Xarelto), Edoxaban (Savasya), Dabigatran (Pradaxa)
List Factor-Xa inhibitors
Apixaban (Eliquis), Rivaroxaban (Xarelto), Edoxaban (Savasya)
List Factor IIa inhibitors
Dabigatran (Pradaxa) (Direct thrombin inhibitor)
Warfarin indications
- Valvular Afib
- Mechanical heart valves
- Some hypercoagulable states
Warfarin MOA
Vitamin K antagonist->decreases hepatic synthesis of factors 2,7,9, and 10, protein C and S by blocking carboxylation
Warfarin route of administration
Oral
Warfarin half-life
20-60 hours~
Warfarin DDI
CYP1A2, CYP2C19, and MAJOR (CYP2C9 and (CYP3A4)
1.Amiodarone, 2.Macrolide Antibiotics (Azithromycin, Erythromycin), 3.-azole antifungals (fluconazole), 4.Sulfa antibiotics (Bactrim), 5. Rifampin
Warfarin monitoring parameters
INR 2-3 (1 considered normal)
Hgb, Hct, platelets
What is the brand name of Apixaban?
Eliquis
Apixaban route of administration
oral
Apixaban AFib Dosing
5 mg twice daily
Apixaban VTE Dosing
10mg twice daily x 1 week, then 5 mg twice daily
Apixaban dose adjustment
Only for AFib! Adjust dose to 2.5mg BID if 2/3 criteria are met:
- SCr > 1.5
- Weight < 60 kg
- Age > 80 years old
Apixaban DDI
Major substrate of CYP3A4
Rivaroxaban brand name
Xarelto
Rivaroxaban route of administration
PO
Rivaroxaban AFib Dosing
20 mg daily WITH FOOD
Rivaroxaban VTE Dosing
15 mg twice daily x 21 days then 20 mg daily WITH FOOD
Rivaroxaban dose adjustment
Afib Only: CrCl 15-50 mL/min then 15 mg daily with food
Avoid use CrCl < 15 mL/min
Rivaroxaban DDI
Major substrate of CYP3A4
Brand name of Edoxaban
Savaysa
Edoxaban route of administration
Oral
Edoxaban dose AFIB
60 mg PO QD
Edoxaban dose in VTE
After 5 days of parenteral anticoagulation: >60kg = 60 mg PO QD ≤60kg = 30 mg PO QD
Edoxaban renal dose adjustment
AFIB: 15-50 ml/min: 30 mg PO QD
Edoxaban use caveat (Renal)
Only use in patients with moderate kidney function CrCl 15-95 ml/min
Fondaparinux brand name
Arixtra
Fondaparinux route of administration
Parenteral: SQ and IV
Avoid fondaparinux in these populations
CrCl < 30 mL/min
Weight < 50 kg
Dabigatran route of administration
Oral
Dabigatran AFib Dosing
150 mg twice daily
Dabigatran VTE Dosing
5 days parenteral then 150 mg twice daily
Dabigatran renal adjustment
Afib:
CrCl 15-29 mL/min 75 mg twice daily
Avoid CrCl < 15 mL/min
VTE:
Avoid CrCl < 30 mL/min
Dabigatran weight consideration
Avoid > 120 kg, BMI ≥ 40 kg/m2
Bivalirudin MOA
Direct thrombin inhibitor
Bivalirudin route of administration
Continuous IV infusion
Bivalirudin half-life
10-24 minutes
Argatroban MOA
Direct Thrombin Inhibitor
Argatroban Route of Administration
Continuous IV Infusion
Argatroban Half-Life
39-51 minutes
Heparin-Induced Thrombocytopenia (HIT) Risk Factors
- Source: Bovine > Porcine
- UFH > LMWH
- IV > SQ
- Surgical patients > Medical/Obstetric
- Longer exposure = higher risk
4T Score Components
- Thrombocytopenia
- Timing
- Thrombosis
- Other Cause
HIT is an indication for therapeutic anticoagulation (T/F)
TRUE!
Components of CHA2DS2VASc Score
C: Congestive HF
H: HTN
A: Age > 75 years (2 pts)
D: Diabetes
S: Stroke/TIA/Systemic Embolism (2 pts)
V: Vascular Disease
A: 75-74 years
Sc: Female
Anticoagulation indicated in men with a CHA2DS2VASc Score ≥ ___
2
Anticoagulation indicated in women with a CHA2DS2VASc Score ≥ ___
3
HASBLED Componenets
H: HTN - SBP > 160 mm Hg
A: Abnormal liver/kidney function (1 each)
S: Stroke history
B: Bleeding history
L: Labile INR
E: Elderly > 65 years
D: Drug/Alcohol abuse (1 each)
Lenient Rate Control HR Goal
< 110 bpm
Patients who qualify for Lenient Rate Control
Asymptomatic AND EF > 40%
Strict Rate Control HR Goal
< 80 bpm
Patients who qualify for Strict Rate Control
Symptomatic OR EF ≤ 40%