Infliximab Safety

Infliximab is a medication used to reduce the symptoms and signs of several chronic inflammatory disorders. It is approved for the treatment of Crohn’s disease, rheumatoid arthritis, psoriasis, ankylosing spondylitis and psoriatic arthritis. Infliximab is also known by the trade name Remicade.

Infliximab is a monoclonal antibody that has been specifically designed to target the cytokine tumor necrosis factor-alpha (TNF-α). This cell signalling protein plays an important role in the abnormal immune response that occurs in inflammatory disorders. Excess production of TNF-α can lead to inflammation that damages the bones, cartilage and other bodily tissues. Infliximab works by blocking the action of TNF-α, thereby suppressing the immune system and reducing inflammation and the associated symptoms.

Due to the effect of infliximab on the immune system, patients receiving the treatment are susceptible to infections, including severe ones such as sepsis and tuberculosis (TB). Pre-treatment screening is therefore essential for patients and doctors will need to know about the following:

• Any recent exposure to TB or whether the patient has not received a BCG vaccination. If a patient has not received this vaccination, they may need to undergo a chest X-ray to check for underlying TB before treatment with infliximab can be started. Many doctors now use a blood test to check for TB prior to administering infliximab.
• Any history of HIV, hepatitis B or C or contact with individuals who have these infections. A blood sample is usually taken to check for these infections before infliximab therapy is initiated.
• History of living in any region where certain fungal conditions such as coccidioidomycosis or histoplasmosis. Examples of these regions are parts of the USA, Africa and south America.
• Any history of cancer, since alteration of immune system function may slightly increase the risk of certain forms of cancer.
• Any current infection. Therapy may need to be postponed until the infection is treated.
• Any contact with individuals who have chickenpox, measles, shingles, or pneumococcal disease. If a patient is not already immune, they may need to be vaccinated against these infections before treatment is started.

A doctor will also need to know about any history of heart problems because infliximab can worsen symptoms. Patients with heart problems will therefore need close monitoring both before and after infliximab therapy. The use of infliximab can also increase the risk of lung cancer and a physician will need to be informed if the patient is a smoker or has chronic obstructive pulmonary disease.

During therapy

Patients are monitored at all stages while they are receiving an infliximab infusion and for around two hours afterwards to check for signs of allergic reaction. Once a patient has begun their treatment programme, they will continue to be checked regularly to prevent complications or ensure any complications that do develop are caught at an early stage.

Patients are advised to try and avoid coming into contact with anyone who has an infection. Even a mild infection such as a sore throat or cold can turn into a more serious illness when patients are taking this drug. People receiving infliximab also need to be aware of any new symptoms that develop and must tell their doctor if they start to feel unwell or think they may have caught an infection. Doctors also advise that patients take care when preparing food and to avoid eating any undercooked meat or raw eggs, for example. Patients are advised to have an annual flu vaccine while receiving infliximab therapy.

Interaction with other medications

Infliximab has been found to interact with several other medications. Some examples of the drugs that may interact with infliximab include the following:

• Anakinra
• Azathioprine
• 6-mercaptopurine
• Abatacept
• Methotrexate

Patients should also advise their doctor of any over-the-counter medications, vitamins, herbal remedies or alternative medicines they are taking.

Alcohol

It is not yet clear whether alcohol interacts with infliximab, but patients are advised that if they do decide to drink alcohol, they do so within the Department of Health guideline limits.

Pregnancy

There is still limited evidence regarding the safety of taking infliximab during pregnancy. Researchers have found that although infliximab does not cross the placenta during the first two trimesters, it can do so during the third trimester. Due to a lack of clear evidence, drug manufacturers do not recommended the use of infliximab in pregnant women. On the other hand, some doctors believe that the treatment should be continued if it is keeping a pregnant woman’s condition in check, at least during the first and second trimester. Recent British Society of Gastroenterology guidelines suggest that doctors discuss the risk with pregnant women on an individual basis.

Breastfeeding

Research has suggested that it may be safe for mothers to breastfeed while taking this therapy because infliximab does not seem to pass into breast milk. However, evidence for this is still limited and most doctors do not advise breastfeeding during treatment or for six months since the last session of therapy.

Immunisations while on infliximab

Receiving certain vaccinations while receiving infliximab may be dangerous. Patients should not be given any “live” vaccines such as those used to immunize against rubella, TB, yellow fever or polio. However, inactivated vaccines such as those used for polio or influenza may be safe and patients should discuss with their doctor whether or not they can receive these vaccines.