Phaemacopeia – Haematology

Master answer

Haemostasis: the physiological processes which arrest bleeding

Drugs which reduce blood flow:

• Adrenaline: causes local vasoconstriction
• Wound glue: physical barrier to reduce bleeding

Drugs which increase the available coagulation factors:

• Desmopressin: increases plasma levels of FVIII and von Willebrand Factor, which promote formation of the platelet plug and participate in the coagulation cascade
• Vitamin K: required for the gamma-carboxylation of coagulation factors II, VII, IX and X to activate them in the clotting cascade. Also activates proteins C and S. Vitamin K may be given to reverse supratherapeutic INR associated with warfarin use; may also be given in liver disease or other situations when the INR is elevated and potential bleeding is a concern.
• Prothrombinex: powder for injection containing 500IU each of FII, IX and X, low levels of FV and VII, 25mg of antithrombin which participate in the coagulation cascade as normal
• Biostate: Human derived FVIII/VWF complex which can participate in the coagulation cascade
• Other factor concentrates

Drugs which reduce clot breakdown:

• Tranexamic acid: acts by inhibiting the binding of plasminogen and plasmin to fibrin, to inhibit fibrinolysis of a formed clot
• Aprotinin: a naturally occurring proteolytic enzyme inhibitor acting on trypsin, plasmin and tissue kallikrein. It inhibits the fibrinolytic activity of the streptokinase-plasminogen complex and decreases activation of the clotting cascade.
• Aminocaproic acid: Binds competitively to plasminogen, blocks the binding of plasminogen to fibrin and subsequent conversion to plasmin, resulting in inhibition of fibrinolysis
• Oestrogen: inhibits Protein C (naturally occurring regulator of haemostasis)

Drugs which reverse anticoagulants:

• Vitamin K: as above
• Protamine sulfate: binds to heparin in circulation to produce a stable inactive complex for removal by reticuloendothelial system. Useful in cases of bleeding associated with heparin use.
• Idarucizumab: specific reversal agent for dabigatran
• Andexanet Alfa: Recombinant protein that inactivates direct factor Xa inhibitors like Rivaroxaban as well as antithrombin activated by LMWH or Fondaparinux

JC 2019

Answer by JC