Infliximab belongs to the class of medications called biological response modifiers ("biologics") or TNF blockers. It is used to treat:

• active ankylosing spondylitis in adults who have not responded to other therapies or who have experienced unacceptable side effects with other therapies
• active psoriatic arthritis in adults
• moderate-to-severe chronic plaque psoriasis in adults (after phototherapy has been shown ineffective or inappropriate)
• moderate-to-severe rheumatoid arthritis in adults when used in combination with methotrexate
• fistulating Crohn's disease in adults who have not responded to other therapies
• moderate-to-severe active Crohn's disease in adults and children older than 9 years of age who have not responded to other therapies
• moderate-to-severe active ulcerative colitis in adults and children older than 6 years of age who have not responded to other therapies

If you have one of these conditions, your body overproduces a protein called tumour necrosis factor (TNF), which causes pain, inflammation, and damage. Infliximab blocks the production of TNF and decreases the inflammation in the joints and on the skin.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended dose of infliximab depends on the condition being treated and varies according to body weight.

It is injected intravenously (into a vein) by a health care professional, usually in a clinical setting such as a hospital clinic, over several hours. This process is called an intravenous infusion. You should keep all your appointments and follow-ups as recommended by your doctor.

The appropriate dose for the following conditions is usually given 2 and 6 weeks after the first dose, then every 8 weeks thereafter:

• Crohn's disease
• rheumatoid arthritis
• ulcerative colitis
• psoriatic arthritis
• plaque psoriasis

For ankylosing spondylitis, the appropriate dose is usually given 2 and 6 weeks after the first dose, then every 6 to 8 weeks thereafter.

It is important to receive this medication exactly as recommended by your doctor. If you miss an appointment to receive infliximab, contact your doctor as soon as possible to reschedule your appointment.

Many things can affect the dose and schedule of medication that a person needs, such as body weight, other medical conditions, and other medications. Your doctor may choose a schedule different from the one above.

This medication must be refrigerated at 2°C to 8°C (do not freeze it) and kept out of the reach of children. This medication does not contain preservatives and must be mixed with sterile water for injection before IV infusion. Once the powder has been mixed, it should be used within 3 hours.

You should not use infliximab if you:

• are allergic to infliximab, mouse proteins, or any ingredients of the medication
• have moderate-to-severe congestive heart failure
• have or are at risk of severe infections such as sepsis, abscesses, tuberculosis, or opportunistic infections (infections that strike people with weakened immune systems)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• back pain
• cough
• diarrhea
• dizziness
• fatigue
• headache
• itch
• upset stomach

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• fever or chills
• joint pain
• shortness of breath
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of heart problems (e.g., fast, irregular heartbeat or pulse, chest pain, sudden weight gain, difficulty breathing, leg swelling)
• signs of nervous system problems (e.g., vision changes, weakness in arms, legs or numbness or tingling in any part of the body)
• skin rash
• symptoms of an infection (e.g., fever, chills, pain, swelling, or pus)
• symptoms of liver damage (e.g., yellow skin or eyes, dark urine, loss of appetite, abdominal pain, fever, and fatigue)
• symptoms of lupus (e.g., chest discomfort/pain, shortness of breath, joint pain, rash on the cheeks or arms)
• symptoms of upper respiratory infections (e.g., sore throat, fever, cough, fatigue, chest congestion)
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)

Seek immediate medical attention if any of the following occur:

• seizures
• symptoms of an allergic reaction (such as difficulty breathing, hives, swelling of the face or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reactions: In rare cases, some people may develop an allergic reaction to this medication. Signs of an allergic reaction include a severe rash, hives, swollen face or throat, or difficulty breathing. If these occur, contact your doctor immediately.

Blood disorders: Rarely, people taking this medication have become deficient in certain types of blood cells. This may lead to problems with blood clotting, the immune system, or the transport of oxygen through the body. Contact your doctor immediately if you develop a fever, easy bruising, paleness, or bleeding while taking this medication.

Cancer: Compared to the general population, people taking infliximab have a slightly greater risk of developing a cancer of the immune system (known as lymphoma). However, the risk of developing this type of cancer is still rare.

In general, people with severe rheumatoid arthritis and Crohn's disease who take medications that suppress the immune system over long periods of time may also have a higher risk of developing lymphoma, even if they don't take infliximab. Contact your doctor if you develop symptoms of lymphoma (such as fatigue, weight loss, fever, swollen glands, night sweats, and itching). (Note though that these may also be symptoms of other conditions.)

Some children and young adults with Crohn's disease who were receiving infliximab have developed hepatosplenic T-cell lymphoma, a rare type of cancer that is often fatal. Talk to your doctor if you have any concerns.

Other forms of cancer, such as cervical and certain skin cancers, have also been seen in people who are taking infliximab. Talk to your doctor about the risks and benefits of using this medication.

Drowsiness/dizziness: Infliximab can cause drowsiness or dizziness, affecting your ability to drive or operate machinery. Avoid driving, operating machinery, or performing other potentially hazardous tasks until you have determined how you are affected by this medication.

Heart failure: This medication may worsen congestive heart failure. If you have mild heart failure you should be closely monitored by your doctor while taking this medication. If you notice symptoms of congestive heart failure (such as swelling of the hands or feet and difficulty breathing), contact your doctor immediately. People with moderate or severe congestive heart failure should not take infliximab.

Hepatitis B: People infected with hepatitis B (an infection that can damage the liver) may have a relapse of their condition while taking this medication. If you are at risk for hepatitis B, your doctor may want to test you for this infection before starting treatment with infliximab and will follow your condition closely while you are taking the medication. If you notice symptoms of a liver problem (see below), contact your doctor immediately.

Immune system disorders: Some people who take this medication have developed lupus-like syndrome, an autoimmune disease (a condition where the body is attacked by its own immune system). Symptoms of lupus-like syndrome include chest pain, joint pain, difficulty breathing, and a skin rash (usually on the cheeks and arms) that is sensitive to the sun. If you develop these symptoms, contact your doctor as soon as possible.

Infections: This medication can increase the risk of developing an infection, including serious infections such as sepsis, pneumonia, and tuberculosis. Before starting infliximab treatment, your doctor may test to see if you have tuberculosis. If you notice signs of an infection such as fever, chills, pain, swelling, coughing or pus, contact your doctor as soon as possible. This medication should also not be started while you have an active infection.

Tell your doctor if you have a history of infections that keep coming back, or other conditions that might increase your risk of infections (e.g., diabetes) or have visited or lived in areas where there is a greater risk of certain kinds of fungal infection (e.g., blastomycosis). While you are taking infliximab, your doctor will monitor you for signs of infection.

Liver problems: Very rarely, people taking infliximab may experience liver problems. Symptoms of liver problems include abdominal pain, dark urine, fatigue, loss of appetite, and yellow eyes or skin. If you notice these symptoms, contact your doctor immediately.

Nervous system disorders: Rarely, this medication may increase the risk of problems with the nervous system or cause existing problems to get worse. If you experience confusion, seizures, vision changes, tingling or numbness, or weakness in your arms or legs while taking this medication, contact your doctor immediately.

Vaccines: Live vaccines (e.g., BCG, yellow fever) are not recommended for people taking this medication. Talk to your doctor if you need any vaccinations while taking this medication. Children with Crohn's should complete the recommended vaccination schedule before receiving their first dose of infliximab.

Pregnancy: This medication is not recommended for use during pregnancy as it crosses the placenta and the effects on the developing baby are not known. Infants born to those who used this medication during pregnancy appear more likely to experience severe and possibly life-threatening infections. Anyone who may become pregnant should use an effective method of birth control while they are taking this medication and for at least 6 months after the last treatment.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and taking infliximab, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of this medication have not been established for children under 6 years old. It can be used to treat children 6 years and older who have moderate-to-severe ulcerative colitis. It can also be used to treat children 9 years and older who have moderate-to-severe Crohn's disease. The safety and effectiveness of this medication for treating other conditions in children have not been established.

Seniors: Seniors may be more likely to experience serious infections with infliximab. Talk to your doctor about the risks and benefits of using this medication.

There may be an interaction between infliximab and any of the following:

• abatacept
• abrocitinib
• adalimumab
• anakinra
• anifrolumab
• azathioprine
• baricitinib
• belimumab
• bimekizumab
• brodalumab
• canakinumab
• certolizumab pegol
• cladribine
• denosumab
• deucravacitinib
• etanercept
• golimumab
• guselkumab
• ixekizumab
• leflunomide
• mercaptopurine
• natalizumab
• ocrelizumab
• ofatumumab
• pimecrolimus
• risankizumab
• rituximab
• ruxolitinib
• sarilumab
• secukinumab
• sphingosine 1-phosphate (S1P) receptor inhibitors (e.g., fingolimod, ponesimod, siponimod)
• tacrolimus
• thioguanine
• tildrakizumab
• tocilizumab
• tofacitinib
• upadacitinib
• ustekinumab
• vaccines (e.g., yellow fever, BCG, cholera, typhoid, varicella)
• vedolizumab

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.