Full Intensity SQ Heparin

Guidelines for Fixed Dose, Full Intensity SQ Heparin

  • 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.)

Guidelines for Adjusted Dose, Full Intensity SQ Heparin

Initial Dosing

Starting therapy with adjusted-dose SQ heparin

  • Give UHF 240 units/kg SQ x 1
  • Check aPTT 6 hours after first dose
  • Adjust dosing according to chart below

Converting from continuous infusion heparin to adjusted dose SQ heparin

  • Calculate 24hr dosing requirement necessary to maintain therapeutic PTT
  • Divide into two q12h doses
  • Discontinue IV heparin and administer first SQ dose within 1 hour
  • Check first PTT 6 hours after first dose
  • Adjust dosing according to chart below

Converting from warfarin to adjusted dose SQ heparin

  • Discontinue warfarin
  • Give heparin 240 units/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

PTT (sec)

Dosing Adjustment

(round to nearest 500 units)

Next PTT

< 40 increase by 36 - 48 units/kg q12h 6 hours after a dose in 1-3 days
40 - 59 increase by 24 - 36 units/kg q12h 6 hours after a dose in 1-3 days
60 - 100 no change q4-7 days (6 hours after a dose)
101 - 120 decrease by 6 - 12 units/kg q12h 6 hours after a dose in 1-3 days
121 - 140 decrease by 12 - 24 units/kg q12h 6 hours after a dose in 1-3 days
> 140 decrease by 24 - 36 units/kg q12h 6 hours after a dose in 1-3 days

 

Therapeutic Monitoring

  • Baseline:  CBC, PT/INR, PTT
  • First 2 weeks of therapy:  CBC q2-3 days
  • Chronic therapy: CBC q1-3 months