Which of the following is an antidote of heparin?
High-Yield Explanation
Intravenous infusion of protamine sulfate is used as antidote of heparin in case of life threatening hemorrhage. Protamines are basic low molecular weight positively charged proteins that have a high affinity for negatively charged heparin molecules. It binds tightly to heparin and thereby neutralizes its anticoagulant effect. Protamine only binds long heparin molecules. Therefore, it only paially reverses the anticoagulant activity of LMWHs and has no effect on fondaparinux. The very sho molecules of fondaparinux do not bind protamine. Heparin acts by binding to antithrombin III and induces a conformational change that accelerates the interaction of antithrombin III with other coagulation factors. Ref: Weitz J.I. (2011). Chapter 30. Blood Coagulation and Anticoagulant, Fibrinolytic, and Antiplatelet Drugs. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e.