Low molecular weight heparin

Background

Enoxaparin (Lovenox)

1. Similar mechanism of action as heparin but with predictable effect
2. LMWHs are defined as heparin salts having an average molecular weight of less than 8000 Dalton. LMWHs inhibit the coagulation process through binding to antithrombin which in turn inhibition activated factor X.
3. Advantages over unfractionated heparin:
   1. More reliable level of anticoagulation
   2. No need for monitoring w/ PTT
   3. Decreased incidence of HIT
   4. Can give as oupt
4. Disadvantages compared to unfractionated heparin:
   1. Renally excreted; may accumulate in pts w/ renal impairment leading to bleeding
   2. Longer half-life

Dosing

1. Renal impairment (Cr clearance <30)
   1. Use 50% of usual dose or use UFH instead
2. Obesity
   1. Weight-based dosing safe up to 190kg (no data available thereafter)

Treatment

1. See:
   1. DVT
   2. PE
   3. NSTEMI
   4. STEMI

Complications

1. Bleeding
   1. Less common than with UFH
   2. Treatment
      1. Protamine
         1. Does not completely reverse LMWHs
         2. Carries significant anaphylaxis risk (0.2%); only use for major bleeding
         3. Dosing
            1. For Enoxaparin: protamine 1mg IV for every 1mg of enoxaparin given in previous 8h
               1. If 8–12h since last enoxaparin dose give 0.5mg IV for every 1mg of enoxaparin given
2. Pruritus
3. Local skin reaction

See Also

• Heparin (Unfractionated)
• Coagulopathy (Main)

Source

Tintinalli