· Warfarin effect
· Warfarin reversal
Drug |
Wisconsin Alumni Research Foundation |
Mechanism |
|
Factors affected (half life) |
· Procoagulants: II (60h), VII (6h), IX (24h), X (36h) · Anticoagulants: protein C (8h), protein S (30h) |
Timeline of effect |
· Initial procoagulant effect o Short half lives of anticoagulant protein C o Long half lives of procoagulants II and X (most important) · Then anticoagulant effect o Onset ~8-12 hours o Peak ~3 days o Duration ~5 days |
Considerations |
· Depends upon urgency of surgery · Depends if actively bleeding · Check INR shortly pre-op to ensure adequate |
Stop and wait |
· Time 3-5 days · t1/2β 40 hours · Need drug elimination + production of new coag factors · ↑Duration if: Vit K deficient e.g. malnourished, CYP inhibitor (e.g. cimetidine), CYP competition e.g. amiodarone · ↓Duration if: CYP inducer (e.g. barbiturates) |
Vitamin K |
· PO 1-2mg for effect in 12-24 hours · IV 5-10mg for effect in 6-12 hours |
Blood products |
· Effect immediate · FFP 10-15mL/kg (note risk of APO); or · FFP 2-4mL/kg + prothrombinex (factors 2, 9, 10) 25-50 units/kg · +/- Activated Factor 7 (if ↑↑INR and bleeding) |
Feedback welcome at ketaminenightmares@gmail.com