Browse Prescribing Notes by Therapeutic Subcategory

It is recommended that all patients with hemophilia be vaccinated for Hepatitis A and B due to the increase risk of infection associated with frequent infusions of blood products.

Hemophilia A
Factor VIII (FVIII) is the specific clotting factor deficient in patients with Hemophilia A, or classical hemophilia. Administration of antihemophiliac factor increases plasma levels of FVIII activity, temporarily corrects the in vitro coagulation defect, and ultimately activates the clotting cascade to form a clot. The development of an inhibitor to FVIII may require treatment with other clotting factors (eg, factor VIIa).

Confirm factor VIII deficiency prior to treatment. Doses recommended are general guidelines; doses required for hemostasis must be individualized according to the needs of the patient, severity of the deficiency, severity of the hemorrhage, the presence of inhibitors and the factor VIII level desired. It is often critical to follow the course of therapy with factor VIII level assays. If an inhibitor is present, dosage can be determined only by the clinical response and may require treatment with alternative products. Inhibitor formation is especially common in young children with severe hemophilia during their first years of treatment, or in patients of any age who have received little previous treatment with FVIII.

Dosage Calculation:
Dosage Required (IU) = Body Weight (kg) × Desired % Factor VIII Increase × 0.5

Hemophilia B
Hemophilia B is the result of a deficiency of clotting Factor IX (Christmas factor) and is an inherited X-linked recessive trait. Factor IX is activated by factor VII/tissue factor complex in the extrinsic coagulation pathway as well as by factor XIa in the intrinsic coagulation pathway. The activation of the clotting cascade will ultimately form a clot.

Dosage Calculation:
Dosage Required (IU) = Body Weight (kg) × Desired Factor IX increase × 1 IU/kg

For Bebulin VH and Benefix use:
Dosage Required (IU) = Body Weight (kg) × Desired Factor IX increase × 1.2 IU/kg

In the presence of Factor IX inhibitor, higher doses may be required.

Von Willebrand Disease
Von Willebrand disease affects platelet function due to a deficiency or abnormality of the Von Willebrand factor (VWF) which prevents platelet adhesion or aggregation. Von Willebrand factor promotes platelet aggregation and platelet adhesion on damaged vascular endothelium; it also serves as a stabilizing carrier protein for the procoagulant protein Factor VIII. The activity of VWF is measured as VWF:RCo.