II. Mechanism

  1. Potentiates Antithrombin III (AT III)
  2. See Intrinsic Clotting Pathway

III. Dosing: Prophylactic for DVT Prevention

  1. Heparin 5000 Units SQ every 8-12 hours

IV. Dosing: Therapeutic Dosing by Weight based Calculations

  1. Measure
    1. Total body weight (TBW) in kilograms
    2. Height in inches
  2. Calculate Lean Body Weight (LBW) in kilograms
    1. Male: 50 + 2.3 x (height in inches - 60)
    2. Female: 45 + 2.3 x (height in inches -60)
  3. Calculate Dosing Weight
    1. Non-Obese
      1. Dosing Weight (kg): TBW above
    2. Obese (TBW > 1.4 x LBW)
      1. Dosing Weight (kg): (0.4 x TBW) + LBW
  4. Calculate Heparin starting doses
    1. Bolus: 80 Units/kg
      1. Maximum: 10,000 units
      2. Round to nearest 100 units
    2. Maintenance: 18 Units/kg/hour
      1. Round to nearest 50 units per hour

V. Labs: Therapeutic Dosing Initial (before Heparin)

VI. Labs: Therapeutic Dosing Recurring Labs

  1. Partial Thromboplastin Time (aPTT)
    1. 6 hours after bolus and then per nomogram
  2. Platelets
    1. Every 3 days
    2. Minimum: 150,000

VII. Protocol: Therapeutic Dosing Nomogram

  1. aPTT under 40
    1. Give 6000 unit bolus
    2. Increase maintenance rate by 6 units/kg/hour
    3. Recheck aPTT in 6 hours
  2. aPTT 40-49
    1. Give 3000 unit bolus
    2. Increase maintenance rate by 4 units/kg/hour
    3. Recheck aPTT in 6 hours
  3. aPTT 50-59
    1. Give 1500 unit bolus
    2. Increase maintenance rate by 2 units/kg/hour
    3. Recheck aPTT in 6 hours
  4. aPTT 60-85
    1. No change in dosing
    2. Recheck aPTT on the next morning
  5. aPTT 86-100
    1. Decrease maintenance rate by 1 unit/kg/hour
    2. Recheck aPTT in 6 hours
  6. aPTT over 100
    1. Stop Heparin for 60 minutes
    2. Decrease maintenance rate by 2 units/kg/hour
    3. Recheck aPTT in 6 hours

VIII. Adverse Effects

  1. Bleeding complications
  2. Heparin Induced Thrombocytopenia

IX. Management: Reversal

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Related Studies

Cost: Medications

heparin (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
HEPARIN SODIUM 10,000 UNITS/ML VIAL Generic $2.47 per ml
HEPARIN SODIUM 5,000 UNITS/ML VIAL Generic $1.19 per ml