Factor IX (Specialist drug)

How it works

It replaces deficient factor IX, restoring its role in the intrinsic coagulation pathway and enabling normal thrombin and fibrin generation.

Prescribing in practice

• Hypersensitivity reactions and development of inhibitory antibodies to factor IX can occur, and inhibitor formation may be associated with allergic reactions, so patients should be observed and assessed for inhibitors.
• Thromboembolic events are a recognised risk, particularly with some products and in patients with risk factors, so it should be used at the lowest effective level.
• The product brand and batch number should be recorded for each administration for traceability.

Monitoring

Monitor factor IX activity and clinical response, and test for inhibitor development if the expected response is not achieved.

Counselling the patient

• Report any rash, wheeze or swelling during or after an infusion, as allergic reactions can occur.
• Keep a record of the product name and batch used for each treatment.

Evidence & guidelines

Factor IX replacement is the standard of care for haemophilia B and is delivered through specialist haemophilia services.