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Low Molecular Weight Heparin
Aka: Low Molecular Weight Heparin, Low-Molecular Weight Heparin, LMW Heparin, LMWH, Ardeparin, Normiflo, Dalteparin, Fragmin, Danaparoid, Orgaran, Tinzaparin, Innohep
- See Also
- Enoxaparin (Lovenox)
- Indications
- Venous Thromboembolism Treatment
- See Anticoagulation in Thromboembolism
- Deep Vein Thrombosis
- Pulmonary Embolism
- Deep Vein Thrombosis Prophylaxis
- General Surgery
- Orthopedic Surgery (Hip, Knee)
- Contraindications (Indications for standard Heparin)
- Previous Deep Vein Thrombosis history
- Ipsilateral DVT
- Two or more DVTs
- Any Venous Thromboembolism
- High risk lesion (e.g. Iliofemoral DVT)
- Pregnancy
- Renal Insufficiency (Creatinine Clearance <30 due to risk of dose stacking and bleeding risk)
- Morbidly obese patients (consider Unfractionated Heparin where BMI>40-45 kg/m2)
- Hepatic Insufficiency
- Active bleeding
- Surgery in prior 5-7 days (However see below)
- Hypercoagulable state
- Protein C Deficiency
- Protein S Deficiency
- Antithrombin III deficiency
- Inability to undergo outpatient treatment
- Noncompliance
- Thrombocytopenia
- Coagulopathy
- Active Peptic Ulcer Disease
- Efficacy: Unstable Angina and Myocardial Infarction
- Significantly better outcomes than standard Heparin
- Randomized trial (n=3171)
- Lower endpoint (death, Myocardial Infarction, Angina)
- 14 days (16.6 vs 19.8%)
- 20 days (19.8 vs 23.3%)
- Fewer revascularization procedures (27 vs 32.2%)
- Reference
- Cohen (1997) N Engl J Med 337:447-52 [PubMed]
- Efficacy
- Comparable efficacy to Heparin in DVT
- References
- Hull (2000) Arch Intern Med 160:229-36 [PubMed]
- Merli (2001) Ann Intern Med 134:191-202 [PubMed]
- Advantages: LMWH over Unfractionated Heparin
- Rarely causes Heparin Induced Thrombocytopenia
- Does not cause paradoxical thrombotic events
- Results in fewer bleeding complications
- References
- Warkentin (1995) N Engl J Med 332:1330-5 [PubMed]
- (1995) Arch Intern Med 155:601 [PubMed]
- Dosing
- General
- Prophylaxis: Consider increasing the dose by 25% when BMI >40 kg/m2
- Treatment: Dose should be based on total body weight (even in obese patients)
- Exception: Fragmin has a maximum dose (unlike other LMWH agents)
- See specific preparation (e.g. Enoxaparin or Lovenox) for adjustments for Renal Function and Obesity
- Deep Vein Thrombosis Treatment
- Enoxaparin (Lovenox)
- Twice daily dosing: 1 mg/kg SQ twice daily
- Avoid once daily dosing of 1.5 mg/kg SQ daily (less effective, esp. in obese patients, and not for home)
- Available in 30 mg vials
- Tinzaparin (Innohep)
- Dose: 175 anti-Xa IU per kg daily
- Dose (ml): (weight in kg) x 0.00875 ml/kg daily
- Deep Vein Thrombosis Prophylaxis
- Ardeparin (Normiflo)
- Initial: 50 U/kg SQ following surgery
- Later: bid for 14 days or until ambulatory
- Dalteparin (Fragmin)
- Low risk
- Initial: 2500 IU SQ 1-2 hours before surgery
- Later: 2500 IU qd for 5-10 days
- High risk
- Initial: 5000 IU SQ the evening before surgery
- Later: 5000 IU qd for 5-10 days
- Danaparoid (Orgaran)
- Initial: 750 U SQ 1-4 hours before surgery
- Later: then 750 U SQ q12h for 7-10 days
- Enoxaparin (Lovenox)
- Initial: 30 mg SQ q12h OR 40 mg daily for 7-10 days
- Increase to 40 mg twice daily for obese patients
- Tinzaparin (Innohep)
- Innohep 3500 IU SQ daily
- Precautions
- Severe Renal Insufficiency
- Unpredictable dose response to LMWH
- CrCl <30 ml/min: See specific preparation regarding dosing (e.g. Enoxaparin or Lovenox)
- CrCl <15 ml/min: Use Unfractionated Heparin
- Obesity (BMI>40)
- Dosing frequency may need adjustment
- Lovenox has been studied at 1 mg/kg up to 190 kg
- For weights above this, follow anti-Xa levels
- Reversal
- Protamine
- Less responsive to Protamine compared with Heparin