EMmedonline

Mechanism of action

• rFVIIa is indicated in treatment of bleeding episodes in hemophilia A or B patients with inhibitors of Factor VIII or Factor IX.

• It promotes hemostasis by activating the extrinsic pathway of the coagulation cascade.

• It forms a complex with tissue factor at the site of injury, thereby activating coagulation factors IX and X.

• Factor Xa in a complex with other factors , then converts prothrombin to thrombin, leading to the formation of a hemostatic plug by converting fibrinogen to fibrin.

Indication & Dose

• Currently it is inidicated world wide only for hemophilia A ,B or Glanzmann's thrombasthenia.

• In Hemophilia the dose is 90 mcg/kg every two hrs until hemostasis is achieved.

• Half life of Factor VIIa is 2 hrs.

• Jean-Louis et al after analysing data from various studies, recommends that factor VII a can be used as adjunctive to use of the blood products to control bleeding in patients with blunt trauma and they also emphasize the need for every attempt to control bleeding by conventional means before considering a trial of rFVIIa. Dose : 100 -140 mcg/kg.

• At present there is no clear cut indicaton for factor VII in trauma patients.

• Dutton et al from large multicentered randomized placebo controlled trial concluded that adminsitration of recombinant factor VIIA didnot show any significant difference in overall mortality, organ failure.

• Rishi et has shown that r FVIIa has no utility in treating severly acidotic, coagulopathic trauma patients with high rates of bleeding. This is because rFVIIa functions gets studded when pH <7.2.

Updated on 25/7/14

Refrence

• Recommendations on the use of recombinant activated factor VII as an adjunctive treatment for massive bleeding – a European perspective by jean-louis vincent et al, biomed central . 2006

• The utility of recombinant factor VIIa as a last resort in trauma. Rishi Mamtani. World Trauma Congress. 2012