von willebrand factor: clinical use

Prescribing considerations

• Initiate and supervise treatment through a clinician experienced in haemostatic disorders.
• Assess baseline factor VIII when rapid haemostasis is required; separate factor VIII replacement may be necessary because this formulation has low factor VIII content.
• Consider hepatitis A and B vaccination for people receiving plasma-derived factor regularly, and maintain product-batch traceability.
• Assess individual thrombotic risk, particularly during repeated treatment or when factor VIII is also given.
• Do not use this product as treatment for haemophilia A.

Contraindications and cautions

• Hypersensitivity to human von Willebrand factor or any formulation component

Monitoring

• Clinical control of bleeding and peri-procedural haemostasis
• Von Willebrand factor activity and factor VIII activity
• Sustained excessive factor VIII levels during repeated treatment
• Early clinical signs of thrombosis in at-risk patients
• Neutralising antibodies when recovery is inadequate or bleeding remains uncontrolled
• Hypersensitivity throughout administration

Clinical pharmacology

Human von Willebrand factor restores platelet adhesion at vascular injury sites and stabilises endogenous factor VIII. The haemostatic effect on platelet adhesion is immediate, while correction of associated factor VIII deficiency is delayed with this low-factor-VIII formulation.

Formulation and product differences

• Plasma-derived powder supplied with water for injections and a transfer system.
• Contains relatively little factor VIII, so it does not immediately correct substantially reduced factor VIII activity.
• Contains human albumin and a small amount of sodium.
• Licensed polypropylene administration sets should be used because adsorption to some equipment may reduce delivery.
• The reconstituted solution should be inspected and used promptly; it must not be frozen.

Injection

Route: Parenteral

Strengths: 1000 units