Paper I
2021 May (Supplementary) (2010 Scheme) · 40 marks · 120 min

Question

Low molecular weight heparins

Q63 marksShort Notes

Answer

LMWH are derived from unfractionated heparin by depolymerization.

Examples: Enoxaparin, Dalteparin

Mechanism of action

  • Predominantly inhibit factor Xa via antithrombin III, with much less effect on thrombin (IIa) compared to unfractionated heparin

Advantages over unfractionated heparin

  • Better bioavailability, predictable dose-response — allows fixed dosing without routine monitoring
  • Longer duration — once/twice-daily SC dosing
  • Lower risk of heparin-induced thrombocytopenia and osteoporosis

Uses

  • DVT/PE prophylaxis and treatment, acute coronary syndromes, anticoagulation in pregnancy

Adverse effects

  • Bleeding
  • Monitoring: anti-factor Xa levels (not aPTT)

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