LMWH Dosing for DVT Treatment in an 80kg Male
For an 80kg male with DVT, administer enoxaparin 80mg subcutaneously every 12 hours OR 120mg subcutaneously once daily. 1, 2
Standard Therapeutic Dosing Regimens
The preferred approach is weight-based dosing using one of two equivalent regimens:
- Twice-daily dosing: 1 mg/kg subcutaneously every 12 hours = 80mg every 12 hours 1, 2
- Once-daily dosing: 1.5 mg/kg subcutaneously once daily = 120mg once daily 1, 2
Both regimens demonstrate equivalent efficacy to dose-adjusted unfractionated heparin for preventing recurrent VTE and have similar major bleeding rates. 3 The twice-daily regimen may provide more consistent therapeutic anticoagulation, while once-daily dosing offers improved compliance and reduced healthcare worker exposure. 1, 2
Treatment Duration and Monitoring
- Initial treatment: Continue for minimum 5-10 days 1, 2
- Baseline testing: Obtain CBC, renal function (creatinine clearance), hepatic function panel, aPTT, and PT/INR 2
- Platelet monitoring: Check platelet count every 2-3 days from day 4 to day 14 to screen for heparin-induced thrombocytopenia 1, 2
- Follow-up monitoring: Hemoglobin, hematocrit, and platelet count every 2-3 days for first 14 days, then every 2 weeks 2
Critical Dose Adjustments Required
Renal Impairment
If creatinine clearance <30 mL/min, do NOT use standard dosing. Enoxaparin clearance is reduced by 44% in severe renal impairment, creating 2-3 fold increased bleeding risk. 4, 2 In this scenario, unfractionated heparin is preferred. 1
Obesity
If BMI ≥40 kg/m², reduce dose to 0.8 mg/kg every 12 hours (64mg every 12 hours for this patient if obese). 4, 2 Standard fixed dosing is inadequate in obese patients. 4
Cancer Patients
Use standard initial dosing (1 mg/kg every 12 hours), but plan for extended treatment duration of at least 3-6 months, with consideration of dose reduction after the first month for long-term therapy. 1, 2
Common Pitfalls to Avoid
- Never switch between enoxaparin and unfractionated heparin due to increased bleeding risk 2
- Failure to check renal function leads to drug accumulation and hemorrhage in patients with CrCl <30 mL/min 4, 2
- Using once-daily dosing for large PE: For hemodynamically significant PE, twice-daily dosing (1 mg/kg every 12 hours) is preferred over once-daily dosing 1
- Inadequate platelet monitoring: Missing HIT can result in catastrophic thrombotic complications 1
Transition to Oral Anticoagulation
If transitioning to warfarin, overlap enoxaparin for minimum 5 days AND until INR >2.0 for at least 24 hours. 1 Start warfarin on day 1 or 2 of enoxaparin therapy. 1