This is the reason why warfarin is slow acting, and has a time lag in its beginning the action. Naturally the coagulation factors which are already present, they keep acting. Synthesis of new coagulation factors is a long process (for example – Factor II- 60 hours, VII – 6 hours, IX – 24 hours, X – 4 hours), and therefore it takes time to inhibit the process of synthesis of new coagulation factors. Whereas warfarin opposes vitamin K and inhibits the synthesis of vitamin K dependent coagulation factors – II, VII, IX, X). This complex inhibits coaulation factors – IIa, IXa, Xa, XIa, XIIa, XIIIa therefore the action of heparin begins instatntaneouly and it starts its anticoagulant effect. Heparin binds and forms a complex with antithrombin III and activates antithrombin. Heparin is used by parenteral route of administration. Calcium complexing agents: Na oxalate, Na citrate, Na edetate – Factor Xa Inhibitors: Rivaroxaban, Apixoban, Betrixaban, Edoxaban Directly acting oral anticoagulants-DOACs) (Non-Vitamin K antagonists) :
Direct thrombin inhibitors (Heparinoids): Hirudin/Lepirudin/Bivalirudin, Argatroban, Danaparoid, Heparan sulfateĤ.Factor Xa Inhibitors: Fondaparinux, Idraparinux, Idrabiotaparinuxġ.Coumarins: Warfarin sodium, Nicoumalone, dicoumarolģ. Low-molecular weight heparins (LMWH)/Fractionated heparins: Enoxaparin, Dalteparin, Reviparin,Tinzaparin, Pamaparin, Nadroparin, Ardeparinģ. In vivo drugs may be RAPIDLY ACTING (which mainly includes HEPARIN and its related drugs, which produce a rapid action and their effect lasts for comparatively short time) and SLOW ACTING (which mainly includes warfarin sodium, which begins the effect slowly and its effect lasts longer)Ģ. Those used to prevent the blood coagulation inside the body for therapeutic purposes are called In vivo anticoagulants and those used to prevent the clotting of blood when the blood is collected for investigations are the In vitro anticoagulants. SAQ/LAQ/Viva Classify anticoagulants with examples.Īnticoagulants prevent blood coagulation. Thrombolytic = Dissolve the thrombus/clot (means tenecteplase, reteplase, alteplase, streptokinase etc which are tissue plasminogen activators which activate plasminogen into plasmin and the plasmin dissolves the clot) Let us be sure about them right at the beginning.Īnticoagulants = Prevent coagulation by affecting the various mechanisms of coagulation: (means – Heparin, Warfarin sodium)Īntiplatelet = Prevent aggregation of platelets (means – low-dose aspirin, clopidogrel etc) There often exists a confusion in the three terms – Anticoagulant, Antiplatelet, and Thrombolytic. Two video sessions will describe anticoagulants, thrombolytics, and antiplatelet agents.
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