Effect of tranexamic acid, t-AMCHA, and its cis-isomer on the complement system in vitro and in vivo: possible relationship between coagulation and complement systems

Protease inhibitors in the treatment of hereditary angioedema

Deficiency of C1 Inhibitor leads to unopposed activation of complement, with localized, unpredictable, and sometimes life-threatening attacks of angioedema. Treatment with plasma-derived C1 Inhibitor rapidly aborts attacks, and may be lifesaving, but is expensive, requires use of a pooled blood product, may need to be repeated and may not be effective in autoantibody mediated angioedema. The antifibrinolytic agents aprotinin, tranexamic acid, and epsilon-aminocaproic acid are useful for prophylaxis and treatment of angioedema, likely by inhibiting plasmin. Specific drugs to replace the deficient C1 Inh have not been reported. The kallikrein inhibitor DX-88 (Dyax) has received orphan drug status in Europe and is undergoing clinical trial in Europe and the USA.

[Drugs inhibiting complement activation]

Complement may be activated by anaesthetic agents as well as contrast media, and so could anaphylactoid reactions be induced. Efficient and harmless complement blocking agents were still lacking. The only agents actually used by anaesthetists were steroids and/or antifibrinolytic drugs. Other agents were not indicated in surgical patients because of their adverse effects and the impossibility of giving them by the intravenous route.