3. Old stuff
          3.1. Old pharm stuff (pre 2009)
              3.1.1. Scrap
                  3.1.1.2. Drugs affecting coagulation
                      3.1.1.2.2. Anticoagulants
 3.1.1.2.2.2. Low-molecular-weight heparins (LMWH) 

Low-molecular-weight heparins (LMWH)

[SH4:p511]

Examples of LMWH include:

  • Enoxaparin
  • Dalteparin

Structure

  • Derived from standard commercial-grade unfractionated heparin by chemical depolymerisation
  • Approximately 1/3 of heparin in size
  • MW = 4000 to 5000 daltons

Pharmacodynamics

 

Comparison with heparin

  • Greater inhibitory effect on activated factor 10
    * Anti-10a : Anti-2a = 2:1 ~ 4:1
    * c.f. For heparin --> 1:1
  • Lower protein-binding
    --> Better bioavailability at low doses
    --> More predictable response
  • Better in DVT prophylaxis in high-risk patients
  • Less binding to endothelial cells
    --> Longer elimination half-time (4 - 5 hours)
  • Therapeutic doses usually do not affect the prothrombin time and APTT
  • Protamine neutralise about 65% of anti-10a activity of LMWH

Trivia

[SH4:p511]

  • Pentasaccharide consists of very low MW heparin
    * Elimination half-time = ~ 24 hours