Coumadin/Warfarin Protocol
Sterling Area Health Center
Coumadin/Warfarin Dosing Guidelines
I.Protocol: Starting Coumadin in GENERAL patients
A.Pointers
1.Loading Warfarin dose is not needed
B.Indications for starting with concurrent Heparin
1.Thrombophilic state (e.g. known Protein C Deficiency)
2.Thromboembolism
C.Indications for starting Warfarin without Heparin
1.Chronic stable Atrial Fibrillation
D.Starting dose of Warfarin
1.Usual: 5 mg PO daily (anticipate therapeutic by day 4-5)
2.High Dose: 7.5 to 10 mg daily
a)If urgency to reach therapeutic level
b)Study: 10 mg start was therapeutic 1.4 days earlier
(1)Kovacs (2003) Ann Intern Med 138:714
3.Low dose: 2.5 mg PO daily
a)Elderly
b)Liver disease
c)High risk of bleeding
II.Alternate Protocol: Starting Coumadin in GERIATRIC patients
A.General
1.Safe
2.Therapeutic INR achieved within 6-7 days
B.Initial Dose: 4 mg daily for first 3 days
C.Dosing protocol after DAY 3 based on PT/ INR
1.INR <1.3: Warfarin 5 mg daily
2.INR 1.3-1.4: Warfarin 4 mg daily
3.INR 1.5-1.6: Warfarin 3 mg daily
4.INR 1.7-1.8: Warfarin 2 mg daily
5.INR 1.9-2.4: Warfarin 1 mg daily
6.INR >2.4: Hold Warfarin, check INR daily
D.References Siguret (2005) Am J Med 118:137
III.Protocol : PT/INR monitoring( general and geriatrics)
1.Obtain baseline PT/INR
2.Monitor INR 2-3 times per week for 1-2 weeks
3.Stop Heparin ( if on concurrent heparin and Warfarin) when 2 consecutive INRs are therapeutic
4.Monitor INR every 2-4 weeks when stable
5.INR 2.2 to 2.3 associated with lowest overall mortality
6.Oden (2002) BMJ 325:1073
IV.Protocol: Adjust Coumadin (based on INR 2 to 3)
A.See Coumadin for other target INR indications
B.INR less than 2
1.Increase weekly Coumadin dose by 5 to 20%
C.INR 3 to 3.5
1.Decrease weekly Coumadin dose by 5 to 15% or
2.Maintain same dose and recheck in 7 days
a)Banet (2003) Chest 123:499
D.INR 3.6 to 5.0
1.Consider withholding one Coumadin dose
2.Decrease weekly Coumadin dose by 10 to 15%
E.INR 5.0 to 10.0
1.Withhold 1 to 2 Coumadin doses
2.Decrease weekly Coumadin dose by 10 to 20%
3.Indications for Vitamin K
a)Risk of bleeding: Vitamin K 1 to 2.5 mg PO x1 dose
b)Surgery in 24 hours: Vitamin K 2 to 4 mg PO x1 dose
F.INR exceeds 10.0
1.Hold Warfarin
2.Vitamin K 3 to 5 mg PO x1 dose
3.Monitor INR daily and consider repeating Vitamin K
4.Anticipate significantly lower INR within 24-48 hours
G.Serious or Life-threatening bleeding (esp. INR >20)
1.Replace Clotting Factors (first-line)
a)Fresh Frozen Plasma (FFP) 15 ml/kg
2.Reverse Warfarin effect
a)Vitamin K 10 mg by slow IV infusion
b)Anticipate Warfarin resistance after dose
c)Avoid in valve replacement
d)Anticipate 16 hour delay in effect
(1)Consider repeat INR at that time
(2)Consider repeating Vitamin K at 12 hours
3.Other
a)Prothrombin Complex Concentrate (PCC) 50 U/kg
V.Resources
A.Point of Care Guide by Mark Ebell, MD
1.
VI.References
A.Ansell (2001) Chest 119(1 Suppl):22S
B.Crowther (2000) Lancet 356:1551
C.Horton (1999) :
D.Gage (2000) Am J Med 109:484
P:\POLICIES\Coumadin dosing guidelines.doc
Updated: 01/28/10
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