I believe warfarin needs time to build up in system to therepeutic dose while heparin is pretty quick. Warfarin is much cheaper then heparin (especially low molecular weight varieties).

So an acute situation, heparin is given immediately-->warfarin is started-->heparin is discontinued-->warfarin is maintained with frequent checks for appropriate dosing/INR.

--Matt

in acute DVT heparin is given to prevent propagation of the clot. In the acute settings the patient is usually admitted in the hospital and heparin is given intravenously for immediate action under nursing supervision. When the patient is discharged from the hospital warfarin is given for convenience since it could be given orally. Furthermore, warfarin requires time for initiation of its action And hence should be given while the patient is still in the hospital And is under heparinization.

Warfarin reduces the plasma concentration and function of vitamin K dependent coagulation factors (prothrombin, factor VII, factor IX and factor X) and inhibitory proteins (protein C and protein S). The half life of these proteins differ. Upon warfarin treatment the plasma concentration of protein C is reduced much faster that the plasma concentration of prothrombin, factor IX and factor X. Steady state conditions regarding the plasma concentration of all vitamin K dependent proteins are achieved after approximately one week of warfarin treatment. Due to the fast reduction in plasma protein C the patient will be in a pro-thrombotic condition until the concentration of all vitamin K dependent factors is reduced to steady-state, i.e. after one week. Heparin is administered in combination with warfarin the first week, because haparin potentiates the inhibitory effect of antithrombin, in order to protect the patient against the increased risk of thrombosis, induced by the effect of warfarin on protein C.

Johannes is absolutely right. The half life of Vit K dependent coagulation is variable. For example factors II (100hrs), FVII (5 Hrs), FIX (20 Hrs), FX (65 Hrs) and inhibitory proteins, Protein C (6 Hrs) and protein S (60 Hrs). Since the half life of protein C and FVII are relatively shorter it takes at least a week's time to achieve steady state concentrations. Thus Heparin should be given first because it is given intravenously and has an immediate effect. Heparin is a conventional anticoagulant drug. Heparin augments the activity of antithrombin 1000 folds and helps in the prevention of the propagation of the clot and also prevents future formation of the clot. As long as the patient is in the hospital the patient continues to receive heparin. Before the patient needs to be discharged and while still in the hospital the patient receives heparin and warfarin together and when the INR is therapeutic the patient is discharged and then continues warfarin.

If for any reason the patient or the physician decides not to use warfarin, then the patient receives heparin while in the hospital and when the patient is discharged, the physician prescribes LMWH (Low Molecular Weight Heparins) to be given subcutaneously. There are at least 4 different LMWHs which are approved by the United States FDA. The physician may decide to prescribe other drugs such as Dabigatran, Apixaban or Rivaroxaban. These are referred to as New Oral Anticoagulant Drugs (NOACs).

Thanks for the education. Indeed, Heparin when administered, has speedy effects in acute cases that need immediate remediation. After the situation becomes manageable, the efficient, better but slow Warfarin is then administered.

heparin indirectly inhibits coagulation factor x (by potentiating antithrombin inhibiting factor x and factor ii/prothrombin and to a lesser extent factor ix and xi for unfractionated heparin) whereas warfarin prevents the activation of coagulation factors ii, vii, ix, x (by disrupting the recyling of reduced vitamin k that’s necessary to activate the coagulation factors).

clinically, heparin is usually given in the inpatient setting while warfarin is given in the outpatient setting. heparin comes in two forms, low molecular weight heparin (lmwh) or unfractionated heparin (ufh). ufh is given iv in a hospital whereas lmwh can be given iv in a hospital or subcutaenously in a hopsital or outpatient. warfarin is a pill that can be swallowed, so it can be taken at home and monitored at warfarin clinics. heparin effect can be quickly started and stopped, it can be monitored with anti xa activity, and it can reversed by protamine.

warfarin takes a few days for its effect to take effect (which is why it’s bridged with heparin), it must be monitored with INR regularly bc its pharmacodynamics vary by diet/comorbidities, and it can be reversed with pcc (prothrombin complex concentrate) or vitamin k.

Informative.

Heparin and its congeners disrupt the function of factor VIII, which is involved exclusively with hemostasis. Warfarin, Fondoparineaux and other anticoagulants disrupt the interaction of tissue factor with factors VII and X that is the engine of embryological development and also the engine of tissue maintenance and tissue repair. Therefore heparin is safe for pregnant ladies and for prolonged use, while warfarin is teratogenic and lethal when used for prolonged periods of time.

Thank you so much that was very helpful

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