Medicines

Examples of TNF inhibitors available in New Zealand

adalimumab (Humira®)
etanercept (Enbrel®)
infliximab (Remicade®)

What are TNF inhibitors?

TNF inhibitors are used to treat certain types of autoimmune conditions (diseases in which the body's defense system or immune system attacks healthy tissues) such as:
- rheumatoid arthritis, psoriatic arthritis
- bowel diseases such as Crohn's disease, ulcerative colitis
- skin diseases such as chronic plaque psoriasis.
TNF inhibitors work by blocking natural inflammatory substances in the body called tumor necrosis factor alpha. This helps to decrease swelling (inflammation) and weaken your immune system, thereby slowing or stopping the damage from the disease.

Subsidy restrictions

TNF inhibitors are expensive medications with a potential for serious side effects. They are used in selected patients when standard treatments have been unsuccessful. In New Zealand TNF inhibitors are funded with restrictions (Pharmac subsidy restrictions). To qualify for subsidy the initial application for treatment must come from an appropriate named specialist, e.g. a rheumatologist, gastroenterologist or dermatologist.

How are TNF inhibitors given?

TNF inhibitors are given by injection.

adalimumab and etanercept are given by subcutaneous injection (into the skin), usually in the thigh or abdomen (tummy area).
- Change the site for each injection.
- Do not inject in an area that is bruised, red, hard, or tender.
infliximab is given by intravenous infusion (as a drip) into the vein.

Monitoring and investigations

TNF inhibitors have the potential for serious side effects, including the increased risk of infection.

Before prescribing a TNF inhibitor, your doctor will test for infections such as tuberculosis (TB), hepatitis, chicken pox.
To monitor the safety of TNF inhibitors and to observe how well they are working, your doctor will order blood tests before you start treatment and regularly while you are on it. Common tests are full blood count, liver function test, C-reactive protein test.

Vaccinations

Before starting on a TNF inhibitor, your doctor will review your immunisation record to ensure you have received all vaccinations recommended on the New Zealand immunisation schedule. Sometimes it may be necessary to plan an immunisation catch-up.

Live vaccinations, such as varicella vaccine, tuberculosis (BCG) and measles, mumps rubella (MMR), must be avoided if you are receiving treatment with a TNF inhibitor and should be completed before starting treatment.
The following vaccines are safe to take while receiving treatment with a TNF inhibitor:
- Hepatitis A and B vaccine
- Influenza vaccine
- Vaccine against pneumococcal infection
- HPV (Human papillomavirus) vaccine

Possible side effects

Side effects	What should I do?
Reaction at the injection site such as bruising, redness, tenderness	Change the site for each subcutaneous injection Tell your doctor or ring HealthLine 0800 611 116
Because TNF inhibitors weaken the body's immune system, they have been associated with infections. These infections may be mild (such as colds, sinusitis) or more severe such as tuberculosis (TB) and septicaemia (infection of the blood)	Contact your doctor immediately if you develop an ongoing cough, weight loss, fever, sore throat, bruising, or bleeding
Signs of an allergic reaction such as muscle or joint pain, fever, rash, intense itching, swelling of the face or hands, sore throat, headache, or difficulty swallowing	Tell your doctor immediately or ring HealthLine 0800 611 116