Heparin Protocols for UWMC

Intravenous Heparin Administration Orders (pdf)

Low-Range IV Heparin Administration Orders (pdf)

Guidelines for Management of Full Intensity SQ Heparin

Fixed Dosing
  • Unfractionated heparin (UFH) 250 units/kg SQ q12h with no aPTT monitoring
  • Consider 333 units/kg SQ loading dose for treatment of acute thrombosis
  • Do not use for treatment of arterial thrombosis (eg. AF, valve replacement, etc.)
Adjusted Dosing
  • Initial Dosing
    • Initial therapy with adjusted-dose SQ UHF
      • Give UHF 240 U/kg SQ x 1
      • Check aPTT 6 hours after first dose
      • Adjust dosing according to chart below
    • Conversion from continuous infusion UFH to adjusted dose SQ UFH
      • Calculate 24hrs dosing requirement necessary to maintain therapeutic aPTT
      • Divide into two q12h doses
      • Discontinue IV UFH and administer first SQ dose within 1 hour
      • Check first aPTT 6 hours after first dose
      • Adjust dosing according to chart below
    • Conversion from warfarin to adjusted dose SQ UFH
      • Discontinue warfarin
      • Give UFH 240 U/kg SQ when INR < lower limit of therapeutic range
      • Check aPTT 6 hours after first dose
      • Adjust dosing according to chart below
  • Maintenance Dosing Adjustments
aPTT (sec) (based on reagent with Tx range 60-100) Dosing Adjustment (round to nearest 500 units) Next aPTT
<40 Increase dose by 36-48 units/kg q12h 6 hrs after a dose in 1-3 days
40-59 Increase dose by 24-36 units/kg q12h 6 hrs after a dose in 1-3 days
60-100 No change q4-7 days (6hrs after a dose)
101-120 Decrease dose by 6-12 units/kg q12h 6 hrs after a dose in 1-3 days
121-140 Decrease dose by 12-24 units/kg q12h 6 hrs after a dose in 1-3 days
>140 Decrease dose by 24-36 units/kg q12h 6 hrs after a dose in 1-3 days
  • Required Monitoring for Either Option
    • Baseline: platelets, Hct, PT/INR, aPTT
    • First 2 weeks of UFH: platelets q2-3 days
    • Ongoing therapy: platelets, Hct q2-4 weeks