Antihemophilic Factor VIII

Indications

Antihemophilic Factor VIII is used for: Hemophilia A

Adult Dose

Minor hemorrhage:( Early joint or muscle bleed,Severe epistaxis) Loading dose 15 IU FVIII:C/kg to achieve a FVIII:C plasma level of approximately 30% of normal; one infusion may be sufficient. If needed, half of the loading dose may be given once or twice daily for 1-2 days. Moderate hemorrhage:(Advanced joint or muscle bleed,Neck, tongue, or pharyngeal hematoma (without airway compromise), Tooth extraction, Severe abdominal pain ) Loading dose 25 IU FVIII:C/kg to achieve a FVIII:C plasma level of approximately 50% of normal, followed by 15 IU FVIII:C/kg every 8-12 hours for the first 1-2 days to maintain the FVIII:C plasma level at 30% of normal. Continue the same dose once or twice daily for up to 7 days or until adequate wound healing is achieved. Life-threatening hemorrhage:(Major surgery, Gastrointestinal bleeding, Neck, tongue, or pharyngeal hematoma (with potential for airway compromise) , Intracranial, intraabdominal, or intrathoracic bleeding, Fractures) Initially 40-50 IU FVIII:C/kg, followed by 20-25 IU FVIII:C/kg every 8 hours to maintain the FVIII:C plasma level at 80-100% of normal for 7 days. Continue the same dose once or twice daily for another 7 days to maintain the FVIII:C level at 30-50% of normal.

Child Dose

Hemophilia A Minor hemorrhage: 15 IU/kg loading dose to achieve FVIII:C plasma level ~30% of normal; THEN may administer half of loading dose qDay or q12hr for 1-2 days if a second infusion necessary Moderate hemorrhage/minor surgery: 25 IU/kg loading dose to achieve FVIII:C plasma level ~50% of normal; THEN administer FVIII:C 15 IU/kg IVq8-12hr for 1-2 days to maintain plasma levels of FVIII:C at 30% of normal; repeat dose qDay or q12hr for up to 7 days or until adequate would healing achieved Severe hemorrhage/major surgery: 40-50 IU/kg loading dose THEN administer FVIII:C 20-25 IU/kg IVq8-12hr to maintain plasma levels of FVIII:C at 80-100% of normal for 7 days; continue dose qDay or q12hr for up to 7 days to maintain FVIII: C levels at 30% to 50% normal

Renal Dose

Administration

Contra Indications

In individuals who have had an anaphylactic or severe systemic reaction to antihemophilic factor or von Willebrand factor preparations.

Precautions

Risk of intravascular haemolysis in patients with blood groups A, B, or AB receiving high doses or repeated doses of factor VIII preparations. Risk of transmission of some viral infections especially hepatitis B and C. Dose requirement may vary in patients with factor VIII inhibitors; thus optimal treatment should be based on clinical response. Monitor platelet counts regularly during treatment. Pregnancy, lactation. Lactation: Excretion in milk unknown; use with caution

Pregnancy-Lactation

Interactions

Adverse Effects

Side effects of Antihemophilic Factor VIII : Allergic reactions e.g. chills, chest tightness, fever, headache, hyperfibrinogenaemia, jittery feeling, lethargy, nausea, vomiting, somnolence, stinging at infusion site, stomach discomfort, tingling, urticaria, vasomotor reactions with rapid infusion.

Mechanism of Action

Factor VIII is required for clot formation and maintenance of haemostasis. It activates factor X in conjunction with activated factor IX. Activated factor X then converts prothrombin to thrombin, which converts fibrinogen to fibrin, and forms a stable clot with factor XIII. Factor VIII is used for replacement therapy in patients with haemophilia A.