Table of Contents

1. General Dosing Guidelines
2. Dosing Adjustments in Obesity
3. Dosing in Renal Impairment
4. Short Term Monitoring
5. Long Term Monitoring
6. Use in Pregnancy

A. 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).

A. Use Total Body Weight (TBW) up to 190kg.

B. If > 190kg:

1. AntiXa level monitoring available:
   • Use TBW and adjust dose downward if necessary based on antiXa levels
2. AntiXa level monitoring NOT available
   • Use TBW and adjust dose downward if necessary if bleeding occurs
     
     

III. Dosing in Renal Impairment

A. If no antiXa monitoring available: Avoid use if Clcr < 30

B. If antiXa monitoring is available, consider the following initial dosing and adjust as necessary based on peak antiXa activity levels:

• Clcr > 60: 1mg/kg q12h
• Clcr 30-60: 0.85mg/kg q12h
• Clcr < 30: 1mg/kg q24h

C. 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 (U/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
0.5-1.0	NO	NO	Next day, then within 1 week
1.1-1.5	NO	Decrease 20%	Before next dose
1.6-2.0	For 3 hrs	Decrease 30%	Before next dose and 4hrs after next dose
> 2.0	Until antiXa level < 0.5 U/mL	Decrease 40%	Before next dose and q12h until antiXa level < 0.5 U/mL

IV. Short Term Monitoring Guidelines

A. Baseline labs:

• PT/aPTT
• HCT
• Plt and q2-3 days during the first 2 weeks of LMWH therapy
• Scr

B. Peak antiXa activity:

• 3 to 4 hrs after dose in patients with:
  • renal impairment (Clcr< 60)
  • obesity (wt > 190kg)
  • unexpected hemorrhage.
• Check after 3rd dose and again if adjustment required.
• Goal:
  • 0.5-1.0 U/mL for bid dosing
  • 1.0-2.0 U/mL for qd dosing

C. Trough antiXa activity:

• At end of dosing interval
• Check before 4th dose and again if adjustment required
• Goal: < 0.5 U/mL
  
  

V. 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.

A. Peak and/or trough antiXa activity: Check at 7-14 days, then q 1-3 months.

B. Scr: Check q 1-3 months.

D. Clcr: Calculate q 1-3 months (adjust dose as necessary).

E. Patient weight: Check q 1-3 months (adjust dose as necessary)

F. Platelets: Check q 1-3 months (routine labs acceptable)

G: Hct: Check q 1-3 months (routine labs acceptable)

VI. Use in Pregnancy

A. 1st and 2nd trimester

Peak/trough antiXa activity: Check q month.

Scr/Clcr: Check/calculate q month.

Patient weight: Check q month.

Hct: Periodic evaluation.

Platelets: Periodic evaluation.

B. 3rd trimester