Indications
Antihemophilic Factor (Factor VIII) is a blood clotting protein given to people with haemophilia A, an inherited condition in which the body does not make enough Factor VIII. It is used to treat and prevent bleeding episodes, to cover surgery or dental procedures, and in some cases for regular prevention (prophylaxis). Some Factor VIII products that also contain von Willebrand factor are used in von Willebrand disease.
How It Works
Blood clotting depends on a chain of proteins called clotting factors. In haemophilia A, Factor VIII is missing or low, so clots form slowly and bleeding lasts longer. The injected Factor VIII temporarily replaces the missing protein, allowing the clotting chain to work and a stable clot to form.
Dosage and Administration
Factor VIII is given as a slow injection into a vein by a doctor or nurse, or by a trained patient or carer at home. The dose is worked out by the haemophilia specialist from body weight, the Factor VIII level in the blood, the type of bleed or surgery, and the response. Use it exactly as prescribed and keep a record of each dose and batch number.
Interactions
No major drug interactions are known. Tell your doctor about all medicines you use, especially blood thinners such as Warfarin or Aspirin and anti-inflammatory painkillers, which can increase bleeding risk.
Contraindications
Do not use if you have had a severe allergic reaction to Factor VIII or to any ingredient of the product, including traces of animal or human proteins listed on the pack.
Side Effects
- Headache, dizziness, nausea or a change in taste
- Reactions at the injection site such as pain or redness
- Fever, chills, rash or itching
- Development of inhibitors (antibodies) that make Factor VIII less effective; bleeding that does not stop as expected may be a sign
Get urgent medical help if you have signs of a severe allergic reaction (hives, chest tightness, wheezing, swelling of the face or throat, fainting) or if bleeding does not stop after a dose.
Pregnancy and Lactation
Haemophilia A is rare in women, and there is limited experience of Factor VIII in pregnancy and breastfeeding. It should be used only if clearly needed and under specialist care.
Precautions and Warnings
- Your doctor may check your blood for inhibitors, especially in the early period of treatment.
- Products made from human plasma carry a very small risk of passing on infections despite screening and virus removal steps; vaccination against hepatitis A and B may be advised.
- Patients with heart risk factors should be monitored, as better clotting may increase cardiovascular risk.
- Learn the correct mixing and injection technique before treating at home.
Overdose
No specific overdose effects have been reported. Very high Factor VIII levels may raise the risk of blood clots. Contact your haemophilia centre if too much has been given.
Therapeutic Class
Blood coagulation factor (antihaemophilic agent).
Storage
Store as directed on the pack, usually in a refrigerator at 2 to 8°C; do not freeze. Some products may be kept at room temperature for a limited time as stated in the leaflet. Use soon after mixing and keep out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.