Guidelines for Dosing and Monitoring of Enoxaparin

Contents

General Dosing Guidelines

  • Initial treatment of acute thrombosis:
    • Enoxaparin 1mg/kg SQ q12h until minimum course of 5 days has been completed and INR is greater than 2.0 (1.5mg/kg q24h may also be used in pts who are not obese [BMI > 27] and who do not have malignancy).
  • Initial anticoagulation in patients with atrial fibrillation, heart valve replacement, LV thrombus, or other cardiovascular indications for anticoagulation:
    • Enoxaparin 1mg/kg SQ q12h.
  • Bridge therapy during prolonged periods of under anticoagulation:
    • Enoxaparin 1mg/kg SQ q12h until INR > lower limit of therapeutic range (1.5mg/kg q24h may also be used in patients whose indication for anticoagulation is DVT/PE or other non-cardiovascular indication for anticoagulation, including patients with malignancy).
  • Bridge therapy before and after invasive or dental procedures:
    • Enoxaparin 1mg/kg SQ q12h initiated when INR < lower limit of therapeutic range and discontinued when INR > lower limit of therapeutic range (1.5mg/kg q24h may also be used in patients whose indication for anticoagulation is DVT/PE or other non-cardiovascular indication for anticoagulation, including patients with malignancy).
  • Long term use in place of warfarin:
    • Enoxaparin 1mg/kg q12h (1.5mg/kg q24h may also be used in patients whose indication for anticoagulation is DVT/PE or other acute non-cardiovascular indication for warfarin, including patients with malignancy).

Dosage Adjustments in Obesity

  • Use Total Body Weight (TBW) up to 190kg
  • If > 190kg
    • AntiXa level monitoring available:
      • Use TBW and adjust dose downward if necessary based on antiXa levels
    • AntiXa level monitoring NOT available:
      • Use TBW and adjust dose downward if necessary if bleeding occurs

Dosing in Renal Impairment

  • If no antiXa monitoring available: Avoid use if Clcr < 30
  • If antiXa monitoring is available, consider the following initial dosing and adjust as necessary based on peak antiXa activity levels:
    • CrCl > 60: 1mg/kg q12h
    • CrCl 30-60: 0.85mg/kg q12h
    • CrCl < 30: 1mg/kg q24h
  • Trough antiXa monitoring may be indicated to evaluate accumulation at the end of the dosing interval. If peak antiXa levels suggest the need for dosing adjustment, consider the following nomogram:
AntiXa Level (units/mL) Hold Next Dose Dosage Change Next AntiXa Level
<0.35 No Increase 25% 4hrs after next dose
0.35-0.49 No Increase 10% 4hrs after next dose
0.5-1 No No Next day, then within 1 week
1.1-1.5 No Decrease 20% Before next dose
1.6-2 For 3 hours Decrease 30% Before next dose and 4 hours after next dose
>2 Until antiXa level <0.5 Decrease 40% Before next dose and q12h until antiXa level <0.5

Short Term Monitoring Guidelines

  • Baseline labs
    • PT/aPTT
    • HCT
    • Platelets (and q2-3 days during the first 2 weeks of LMWH therapy)
    • Serum creatinine
  • Peak antiXa levels
    • 3-4 hrs after dose in patients with:
      • Renal impairment
      • Obesity (wt > 190kg)
      • Unexpected hemmorhage
    • Check after 3rd dose and again if adjustment required
    • Goal:
      • 0.5-1 units/mL for BID dosing
      • 1-2 units/mL for Qday dosing
  • Trough antiXa levels
    • At end of dosing interval
    • Check before 4th dose and again if adjustment required
    • Goal: < 0.5 U/mL

Long Term Monitoring Guidelines

Although LMWHs typically do not require therapeutic monitoring, under certain circumstances (changing weight, changing renal function, changing health status, etc), patients undergoing long-term therapy may require therapeutic monitoring. Suggests for long-term monitoring under these and other circumstances are described below.

  • Peak and/or trough antiXa activity: Check at 7-14 days, then q 1-3 months
  • Serum creatinine: Check q 1-3 months
  • Creatinine clearance (CrCl): Calculate q 1-3 months (adjust dose as necessary)
  • Patient weight: Check q 1-3 months (adjust dose as necessary)
  • Platelets: Check q 1-3 months (routine labs acceptable)
  • Hct: Check q 1-3 months (routine labs acceptable)

Use in Pregnancy

  • 1st and 2nd Trimester
    • Peak/Trough antiXa level: Check q month
    • Serum creatinine/CrCl: Check/calculate q month
    • Patient weight: Check q month
    • Hct: Periodic evaluation
    • Platelets: Periodic evaluation
  • 3rd Trimester
    • Peak/Trough antiXa level: Check q 2 weeks
    • Serum creatinine/CrCl: Check/calculate q 2 weeks
    • Patient weight: Check q 2 weeks
    • Hct: Periodic evaluation
    • Platelets: Periodic evaluation