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Warfarin Inpatient Nomogram including dose prediction equation

>Beta<  Version 1.0  - Date: July 2013
Patient Parameters
Age:      Specify race:  
Height
:     Weight:
Other (used to predict maintenance dose):
Target INR  Patient receiving amiodarone:  
 Smoker:    DVT /PE present?:

Starting Dose:

Usual starting dose for most patients: 5 mg (Usual range: 4 -10 mg)

Select starting dose:     mg   (Return to this form if you need to alter the dose)
  
9th ACCP suggestion:   Patients healthy enough to be treated as outpatients:  Give warfarin 10 mg daily x 2 days. Further dosing should be based on INR monitoring. (Preferred to starting with an estimated maintenance dose.)   (Grade 2C)

9th ACCP suggestion:   Patients with acute VTE should be started on warfarin on day 1 or 2 of LMWH or heparin therapy e.g. do not wait several days to start treatment.  (Grade 2C)


9th ACCP suggestions:  

-For pt's started on UFH:  Use weight-adjusted  initial bolus of 80 units/kg followed by 18 units/kg per hour for VTE;   or  bolus of 70 units/kg  followed by 15 units/kg per hour for cardiac or stroke patients) or use of a fixed dose (bolus 5,000 units followed by 1,000 units/hour) rather than alternative regimens (Grade 2C) .

-For outpatients with VTE treated with subcutaneous UFH: use weight-adjusted dosing (first dose 333 units/kg, then 250 units/kg) without monitoring rather than fixed or weight-adjusted dosing with monitoring (Grade 2C) .

-For patients receiving therapeutic LMWH who have severe renal-insufficiency (calculated CRCL <30 mL/min): Dose reduction is preferred rather than using standard doses (Grade 2C) .

-Pt's with VTE and body weight > 100 kg: fondaparinux  treatment dose should be increased from the usual 7.5 mg to 10 mg daily SC (Grade 2C) .

Source:
Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ, Svensson PJ, Veenstra DL, Crowther M, Guyatt GH; American College of Chest Physicians.  Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.   Chest. 2012 Feb;141(2 Suppl):e152S-84S. doi: 10.1378/chest.11-2295.

Equations  Used:

BSA

1]  (Weight) kg0.425 x   (Height) cm0.725 x  0.007184 = BSA in M2
    
Reference
: DuBois D, DuBois DF. A formula to estimate the approximate surface area if height and weight be known. Arch Int Med 1916;17:863-71.




Warfarin Dose Prediction

2]   exp [0.613 + (0.425 x BSA) - (0.0075 x age)  + (0.156 x African-American race)
            + (0.216  x target INR) - (0.257 x amiodarone) + (0.108  x smokes) 
                + 0.0784  x  DVT/PE ]

Reference:  Gage BF, Eby C, Johnson JA, Deych E, Rieder MJ, et al. Use of pharmacogenetic and clinical factors to predict the therapeutic dose of warfarin. Clin Pharmacol Ther. 2008 Sep;84(3):326-31. Epub 2008 Feb 27.


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Warfarin Inpt Nomogram and Dose Estimation