How does Enbrel work?
Enbrel injection contains the active ingredient etanercept, which is a type of medicine called a TNF blocker. It works by suppressing the process of inflammation.
Tumour necrosis factor alpha (TNF alpha) is a protein produced by the body that is involved in causing inflammation. It controls the activity of other inflammatory chemicals.
TNF alpha is found in increased levels in various inflammatory conditions. It is found in the inflamed joints of people with rheumatoid arthritis and in the joints of people a form of arthritis affecting the spine, called ankylosing spondylitis. It is also found in increased levels in skin affected by psoriasis, as well as in the joints of people with a form of arthritis called psoriatic arthritis, which can occur in people with psoriasis.
To cause inflammation, TNF alpha has to act on TNF receptors that are found on the surface of cells. Etanercept works by stopping TNF alpha from acting on these receptors. This prevents the inflammatory responses TNF causes. In all the conditions mentioned, etanercept reduces the inflammation and related symptoms.
In arthritic conditions, treatment with etanercept reduces the movement of inflammatory cells into inflamed areas of the joints. This reduces the signs and symptoms of the arthritis, improves physical function of the joints and reduces the rate of joint damage. It also reduces the presence of other inflammatory markers. When treating arthritis, etanercept is referred to as a disease-modifying antirheumatic drug or DMARD.
In plaque psoriasis, etanercept reduces the skin inflammation and thickened scaly plaques of skin.
Etanercept is only prescribed by specialists in these diseases. It is administered as an injection under the skin (subcutaneously) once or twice a week, depending on the condition being treated.
What is Enbrel used for?
Warnings before taking this drug
- Moderate to severe rheumatoid arthritis: Etanercept is used in combination with methotrexate, when other disease modifying antirheumatic drugs (DMARDs, eg sulfasalazine, methotrexate) have not been effective. It can also be used for people with severe active progressive rheumatoid arthritis who have not previously been treated with methotrexate. Etanercept can also be used on its own for people who can't take methotrexate, or when continued treatment with methotrexate is inappropriate.
- Arthritis with no known cause affecting several joints, in children aged 4 to 17 years (polyarticular juvenile idiopathic arthritis): Etanercept is used to treat children with this condition when methotrexate has not been effective or has caused unacceptable side effects. It has not been studied in children under four years of age.
- A form of arthritis that occurs predominantly in young men and affects the joints of the spine (ankylosing spondylitis): Etanercept is used for adults who have severe symptoms of this condition and who have responded inadequately to conventional therapy.
- A form of arthritis called psoriatic arthritis that can occur in people with the skin condition psoriasis: Etanercept is used for adults with active progressive disease that has not responded to treatment with other disease modifying antirheumatic drugs (DMARDs, eg sulfasalazine, methotrexate).
- Moderate to severe plaque psoriasis: Etanercept is used to treat adults with this condition who have failed to respond to, or who cannot take other systemic therapies, including ciclosporin, methotrexate or PUVA.
- This medicine can compromise the body's ability to fight infections. Cases of tuberculosis (TB) and other serious infections have been seen in people treated with this medicine. You should be tested for TB before treatment is started. It is very important to tell your doctor if you have ever had tuberculosis or have been in contact with someone who has tuberculosis. Tell your doctor immediately if you experience weight loss, fever or persistent coughing during treatment, as these can be symptoms of TB.
- It is important to try and avoid exposure to infections, in particular chickenpox, during your treatment. Let your doctor know as soon as possible if you get any symptoms of any infection, so that it can be treated without delay. If you develop a serious infection, treatment with this medicine should be stopped until the infection is controlled. If you or your child has been exposed to chickenpox you should let your doctor know straight away, as he may need to stop your treatment temporarily and administer antibodies to prevent the infection. Your doctor may want to continue to monitor you for infections for a period of time after treatment with this medicine is stopped.
- On rare occasions, this medicine may decrease the number of blood cells in the blood. A low white blood cell count can increase your susceptibility to infections; a low red blood cell count causes anaemia and a low platelet count can cause problems with blood clotting. For this reason, you should tell your doctor immediately if you experience any of the following symptoms during your treatment, as they may indicate problems with your blood cells: unexplained bruising or bleeding, purple spots, sore mouth or throat, mouth ulcers, high temperature (fever) other signs of infection, or looking pale, feeling tired, breathless, or generally unwell. Your doctor may need to take a blood test to check the levels of blood cells in your blood.
- If you develop shortness of breath or swelling of your feet or ankles during treatment with this medicine you should tell your doctor.
- Consult your doctor immediately if you experience any of the following symptoms while receiving treatment with this medicine: unexplained confusion, numbness, changes in vision or difficulty walking.
- If you are due to have any surgery or dental procedures, it is important to tell your doctor or dentist that you are having treatment with this medicine.
- Women who could get pregnant should use an effective method of contraception to prevent pregnancy during treatment with this medicine. Ask your doctor for further advice.
- Enbrel should be stored in a refrigerator at 2 degrees C - 8 degrees C. Do not freeze.
Dosage and administration
Adult dosage for RA (Rheumatoid Arthritis), AS (ankylosing spondylitis) and Psoriatic Arthritis Patients
The recommended dose of Enbrel for adult patients with rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis is 50 mg per week given as a subcutaneous (SC) injection using either an Enbrel SureClick autoinjector or a single-use prefilled syringe.
Moderate to severe juvenile idiopathic arthritis (JIA):
The recommended dose of Enbrel for pediatric patients ages 2 to 17 years with moderate to severely active polyarticular JIA is 0.8 mg/kg per week (up to a maximum of 50 mg per week). For pediatric patients weighing 63 kg (138 pounds) or more, the weekly dose of 50 mg may be administered using Enbrel SureClick autoinjectors or prefilled syringes.
For pediatric patients weighing 31 to 62 kg (68 to 136 pounds), the total weekly dose should be administered as two subcutaneous (SC) injections, either on the same day or 3 or 4 days apart using a 25 mg/0.5 mL prefilled syringe or the multiple-use vial. The dose for pediatric patients weighing less than 31 kg (68 pounds) should be administered as the single SC injection once weekly using the correct volume from the multiple-use vial. Concurrent use with methotrexate and higher doses of Enbrel have not been studied in pediatric patients.
Use with caution at following conditions
The drug should not to be used at
- Dormant (currently inactive) tuberculosis infection.
- History of recurrent infections.
- People who are or who have recently been receiving treatment that suppresses the activity of the immune system (eg long-term oral corticosteroids, chemotherapy, radiotherapy, medicines to prevent transplant rejection).
- People at risk of infections.
- History of decreases in the numbers of blood cells in the blood.
- Advanced or poorly controlled diabetes.
- History of hepatitis B or C.
- Heart failure.
- Demyelinating disorders such as multiple sclerosis.
- Swelling of the optic nerve resulting in blurring of vision (optic neuritis).
- Inflammation of the spinal cord (transverse myelitis).
- Allergy to latex (the needle cover of the syringe contains latex).
- Active tuberculosis.
- Infections due to lowered resistance of the body (opportunistic infections).
- Infection of the blood or body tissues with pus-forming or other pathogenic organisms (sepsis) and people at risk of sepsis.
- Any other active infections, including long-term or localised infections.
This medicine should not be used if you are allergic to one or 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.
- There is no information about the safety of this medicine during pregnancy. It is not recommended for use during pregnancy as it could potentially be harmful to a developing baby. Women who could get pregnant should use an effective method of contraception to prevent pregnancy during treatment. If you think you could be pregnant at any point during treatment you should tell your doctor straight away. Seek further medical advice from your doctor.
- It is not known if this medicine passes into breast milk, however it is likely that it does. For this reason, women having treatment with this medicine should not breastfeed. Seek further medical advice from your doctor.
Enbrel 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 does not mean that all people using this medicine will experience that or any side effect.
- Bacterial, viral or fungal infections, sometimes serious.
- Reactions such as pain, swelling, redness, bruising, bleeding or itching at the injection site.
- Allergic reactions.
- Skin reactions such as rash or itching.
- Decreased numbers of red blood cells, white blood cells or platelets in the blood.
- Nerve disorders.
- Asthma or shortness of breath.
- New or worsening heart failure.
- Chest pain.
- Pins and needles or numb sensations.
- Increased or decreased blood pressure.
- Inflammation of the pancreas (pancreatitis).
- Bleeding from the gut.
- Blood clot in a blood vessel (deep vein thrombosis or pulmonary embolism).
- Kidney problems.
The side effects listed above may not include all of the side effects reported by the drug'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?
Since this is a relatively new medicine, there is limited information about its potential interactions with other medicines. You should tell your doctor if you are taking any other medicines, including over-the-counter and herbal medicines, before you start treatment with this medicine. Similarly, always seek advice from your doctor or pharmacist before taking any new medicines while you are receiving treatment with this medicine, so they can check that the combination is safe.
Etanercept is not recommended for use in combination with anakinra, as this combination may increase the risk of serious infections, without an increase in efficacy against the disease treated.
Etanercept is not recommended for use in combination with abatacept, as this combination may increase the risk of side effects, without an increase in efficacy against the disease treated.
There may be an increased chance of a fall in the numbers of white blood cells in the blood if etanercept is used in combination with sulfasalazine.
This medicine suppresses part of the immune system. This means that vaccines may potentially be less effective if given during treatment, and live vaccines may cause serious infections. Live vaccines include: measles, mumps, rubella, MMR, oral polio, oral typhoid and yellow fever. It is recommended that live vaccines are not given to people being treated with this medicine. Where possible, children receiving this medicine should have all their recommended childhood vaccinations brought up to date before treatment with this medicine is started.
This article is for informational purposes only. For further instructions on Enbrel consult with your doctor.