Haematological (Heparins - Unfractionated Heparin)

Question 1

Examples of drug (Heparins - Unfractionated Heparin)

Answer 1

• Unfractionated Heparin

Question 2

Mechanism of action (Heparins - Unfractionated Heparin)

Answer 2

• Enhances activity of antithrombin III.
• Antithrombin III inhibits thrombin.
• Heparins also inhibit multiple other factors of the coagulation cascade.
• This produces its anticoagulant effect.

Question 3

Indications (Heparins - Unfractionated Heparin)

Answer 3

• Treatment and prophylaxis of thromboembolic diseases, including induction of vitamin K antagonists.
• Renal dialysis (haemodialysis)
• ACS treatment

Question 4

Side effects (Heparins - Unfractionated Heparin)

Answer 4

• Bleeding (Major haemorrhage risk can be as high as 3.5%)
• Heparin-induced thrombocytopenia
• Osteoporosis

Question 5

Important pharmacokinetics/pharmacodynamics (Heparins - Unfractionated Heparin)

Answer 5

• Administered by continuous intravenous infusion or subcutaneous injection
• Complex kinetics - non-linear relationship between dose / half-life and effect – needs TDM
• Effect monitored using activated partial thromboplastin time (aPTT)
• Anticoagulant effect can be reversed with protamine.
• Unfractionated heparin has a shorter duration of action than LMW Heparin.
• Used in preference to LMW Heparin, in selected patients, due to the shorter duration of action and reversibility with protamine (for example, Peri-operatively.)

Question 6

Patient information (Heparins - Unfractionated Heparin)

Answer 6

• Risk of bleeding

- Regular blood monitoring required