Prothrombin concentration factor

The most important adverse effect is bleeding. With coumarins, this can be counteracted by giving vitamin Ki. Coagulability of blood returns to normal only after hours or days, when the liver has resumed synthesis and restored sufficient blood levels of clotting factors. In urgent cases, deficient factors must be replenished directly (e.g., by transfusion of whole blood or of prothrombin concentrate). 

Coumarins are competitive inhibitors of vitamin K, which is required for the formation in the liver of the amino acid, gamma-carboxyglutamic acid. This is necessary for the synthesis of prothrombin and factors VII, IX and X (Figure 17.1). After starting treatment the anticoagulant effect is delayed until the concentration of normal coagulation factors falls (36-72 h). The effects can be reversed by vitamin K (slow maximum effect only after 3-6 h) or by whole blood or plasma (fast). Gut bacteria synthesise vitamin K and thus are an important source of this vitamin. Consequently, antibiotics can cause excessive prolongation of the prothrombin time in patients otherwise adequately controlled on warfarin. 

Prothrombin complex concentrates In a retrospective chart review of 72 patients who received activated prothrombin complex concentrate factor Vni inhibitor bypassing activity and 69 patients who received fresh-firozen plasma to reverse the effects of warfarin during life-threatening bleeding, the former resulted in lower INR and a shorter time firom drug administration to an INR of 1.4 or less [68. There were no significant differences in survival or in the length of hospital stay. There were five adverse events that could have been related to the prothrombin... 

Wojcik C, Schymik ML, Cure EG. Activated prothrombin complex concentrate factor VIII inhibitor bypassing activity (FEIBA) for the reversal of warfarin-induced coagulopathy. Int J Emerg Med 2009 2(4) 217-25. 

Recombinant factor Vila may be considered as an alternative to prothrombin complex concentrate... 

Factor IX Replacement Hemophilia B therapy may include recombinant (produced via transfection of mammalian cells with the human factor IX gene) or plasma-derived (concentrate from pooled plasma) factor IX (see Table 64-2). Guidelines for choosing the factor-concentrate formulation for hemophilia B are similar to the guidelines for hemophilia A. However, older-generation factor IX concentrates containing other vitamin K-dependent proteins (e.g., factors II, VII, and IX), called prothrombin complex concentrates (PCCs), have been associated with thrombogenic side effects. Consequently, these products are not first-line treatment for hemophilia B.11... 

APCC, activated prothrombin complex concentrate PCC, prothrombin complex concentrate vWF, von Willebrand factor. 

Treatment algorithm for the management of patients with hemophilia A and factor VIII antibodies. BU, Bethesda unit PCC, prothrombin complex concentrate a PCC, activated prothrombin complex concentrate. 

II Prothrombin deficiency 30-40% 3 days Prothrombin complex concentrates (intermediate purity factor IX concentrates)... 

VII Factor VII deficiency 30% 4-6 hours FFP Prothrombin complex concentrates (intermediate... 

Freeze-dried concentrates of plasma containing prothrombin, factors IX and X, and varied amounts of factor VII (Proplex, etc) are commercially available for treating deficiencies of these factors (Table 34-3). Each unit of factor IX per kilogram of... 

Note ACE = angiotensin-converting enzyme INR = international normalized ratio PT = prothrombin time PTT = partial thromboplastin time ECG = electrocardiogram PAF = platelet-activating factor AUC = area under the concentration/time curve. 

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