Benefix (Factor IX)

How does it work?

Benefix injection contains the active ingredient nonacog alfa, which is a genetically engineered version of clotting factor IX. Factor IX is a protein that is essential for the process of blood clotting (coagulation). It is found in human plasma.

When bleeding occurs the body quickly seals the breaks in blood vessels by forming clots. A series of clotting proteins is involved in this process. Lack of any one of these clotting factors can lead to uncontrolled bleeding or excessive bruising following injury.

Factor IX is deficient from birth in people with haemophilia B. This deficiency causes the blood to clot very slowly and can result in prolonged bleeding following any injury or wound. People with haemophilia may also bleed spontaneously into muscles and joints.

Factor IX is given to people with haemophilia B to supplement their deficient factor IX. This is necessary to help the blood clot and stop bleeding following accidents, surgery or spontaneous bleeds. In severe cases it may also be given regularly every few days to prevent bleeding.

Nonacog alfa is a form of factor IX that is produced by recombinant DNA technology. It is a relatively newly developed medicine that has the advantage of not containing human proteins, unlike other factor IX products that are obtained from blood given by donors. This means that it does not carry a risk of contracting blood-borne viruses, such as HIV or hepatitis C.

What is it used for?

  • Prevention and treatment of bleeding in haemophilia B, which is a disease where there is a deficiency from birth of a protein necessary for blood clotting called factor IX.

How is it given?

  • Benefix is given by a drip (infusion) into a vein.


  • Allergic reactions are possible to this medicine. If you get symptoms such as hives, tightness of the chest, wheezing, dizziness or nausea you should tell your doctor straight away. These may be early signs of hypersensitivity, or a severe allergic reaction called anaphylaxis. If you get an allergic reaction the medicine should be stopped immediately. If you have an allergic reaction it could suggest you have developed an inhibitor (see below).
  • People being treated with this medicine can sometimes develop antibodies against the factor IX. These are known as inhibitors and they can stop the medicine working properly. If you experience an allergic reaction, or your bleeding is not being controlled with this medicine you should let your doctor know immediately, as you may have developed an inhibitor and your doctor may want to carry out tests to confirm this.

Use with caution in

  • People with a risk of blood clots in the blood vessels (thrombosis or disseminated intravascular coagulation (DIC)) or who have had thromboembolic complications in the past.
  • People with liver disease.
  • People having surgery.

Not to be used in

  • People who are allergic to hamster proteins.
  • Benefix is not recommended for children under six years of age, as it has not been studied in this age group.

This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • Haemophilia B in women is rare, so this medicine has not been studied in women who are pregnant or breastfeeding.
  • The safety of this medicine during pregnancy has not been established. It should only be used to treat pregnant women if the potential benefits outweigh any possible risks to the unborn child. Seek medical advice from your doctor.
  • The safety of this medicine during breastfeeding has not been established. It should only be used to treat breastfeeding women if the potential benefits outweigh any possible risks to the nursing infant. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Uncommon (affect between 1 in 100 and 1 in 1000 people)

  • Development of neutralising antibodies (inhibitors) to factor IX. See warning section above.
  • Dizziness.
  • Lightheadedness.
  • Headache.
  • Feeling sick.
  • Change in taste.
  • Burning and stinging at the infusion site.
  • Phlebitis (inflammation of the wall of the vein).
  • Bacterial infections of the skin or soft tissue, eg cellulitis.

Rare (affect between 1 in 1000 and 1 in 10,000 people)

  • Being sick.
  • Fever.
  • Allergic reactions including rashes, chills, low blood pressure, wheezing, chest tightness, swelling of lips and throat (angiodema). See the warning section above.
  • An extreme allergic reaction (anaphylaxis).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

This medicine is not known to affect other medicines. However, before taking any other medicines or having other treatments it is important that you tell your pharmacist or the health professional that is treating you that you suffer from haemophilia B.

Other medicines containing the same active ingredient

AlphaNine, Haemonine, Mononine and Replenine-VF are other brands of clotting factor IX that are prepared from plasma from screened blood donors.