Inhibitors

An inhibitor is an antibody that attacks the clotting factor given as treatment. The dose that used to stop a bleed may stop working. This is more common in severe haemophilia A than in haemophilia B, and it needs a specialist plan.

Inhibitors often appear in childhood, after the first exposures to factor, but they can appear later. Warning signs are a bleed that does not settle after the usual dose, or bleeds that become more frequent. Only a blood test, called an inhibitor assay or Bethesda assay, can confirm it.

What the centre may do

Repeat the factor level and send an inhibitor test.
Treat a serious bleed with a bypassing product or another medicine the specialist chooses. Product names change, and stock in Nepal is not guaranteed.
Consider immune tolerance therapy, which means regular factor under a strict plan to teach the immune system to stop attacking it. This uses a large amount of factor and is not available in every hospital.
For some people with haemophilia A and inhibitors, a non-factor therapy may be discussed if the centre can obtain it.

Do not increase the dose on your own and do not switch products because a relative was given something else. Haemophilia B inhibitors can, rarely, cause a severe allergic reaction. That is a reason to infuse where help is close until the centre says home treatment is safe.

NHS can help a family prepare questions and can advocate when a child with an inhibitor cannot get a product. The medical decision stays with the treatment centre.

Treatment types

How replacement, prophylaxis and newer therapies differ.

Treatment centres

Where to ask for an inhibitor test and a referral.

Newly diagnosed

The first months are when many inhibitors appear.

This page is general information from Nepal Hemophilia Society. It is not a diagnosis or a treatment plan. A bleed, a head injury, or bleeding after an accident needs urgent hospital care. Ask your treatment centre before you change any treatment.