How does this medication work? What will it do for me?

Cetuximab belongs to the class of medications called antineoplastics. Specifically, it is part of the group of medications known as monoclonal antibodies. It works by attaching to cancer cells, resulting in a decrease in tumour growth and increase in tumour cell death.

This medication is used by itself or in combination to treat certain forms of cancer of the colon or rectum that has spread to other areas of the body (metastatic colorectal cancer). Cetuximab is also used in combination with radiation to treat advanced squamous cell carcinoma (a type of skin cancer) of the head and neck areas.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

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 taking this medication, speak to your doctor. Do not stop taking 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.

What form(s) does this medication come in?

Each mL of sterile, clear, colourless liquid for intravenous administration contains 2 mg of cetuximab. Nonmedicinal ingredients: sodium phosphate dibasic heptahydrate, sodium phosphate monobasic monohydrate, sodium chloride, sodium hydroxide (NF as 10 M Solution For pH adjustment), hydrochloric acid (NF as 6 M Solution For pH adjustment), water for injection.

How should I use this medication?

Cetuximab doses are based on body size. For both colorectal cancer treatment and treatment of squamous cell carcinoma of the head and neck, the recommended first dose of cetuximab, is 400 mg per m² of body surface area. After this, a dose of 250 mg per m² of body surface area is given at weekly intervals. Your doctor will calculate the appropriate dose, based on body size.

Cetuximab is given by intravenous (into a vein) infusion. Cetuximab is usually injected into a vein through a site on your skin that has been specially prepared for this purpose. Very careful handling of this medication is required. It is always given under the direct supervision of a doctor in a hospital or similar setting with access to sterile equipment for preparation.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

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

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use this medication if you are allergic to cetuximab or any ingredients of the medication.

What side effects are possible with this medication?

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
  • acne-like rash
  • constipation
  • diarrhea
  • dry mouth
  • dry skin
  • fatigue
  • general feeling of being unwell
  • headache
  • heartburn
  • increased skin sensitivity to sunlight
  • loss of appetite
  • muscle aches
  • nausea
  • swelling at the base of finger and toenails
  • vomiting
  • weakness
  • weight loss

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

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

  • hand-foot syndrome (e.g., redness, swelling and pain on the palms of hands/soles of feet)
  • mouth sores
  • shortness of breath
  • signs of anemia (low red blood cells; e.g., dizziness,  pale skin, unusual tiredness or weakness, shortness of breath)
  • signs of dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
  • signs of electrolyte imbalance (e.g., muscle pain or cramps, weakness, irregular heartbeat, lack of coordination, thirst, confusion)
  • signs of fluid build-up around the lungs (e.g., chest pain, cough, hiccups, rapid breathing)
  • signs of heart problems (e.g., fast, irregular heartbeat or pulse, chest pain, difficulty breathing)
  • signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • signs of kidney problems (e.g., increased urination at night, decreased urine production, blood in the urine)
  • symptoms of a urinary tract infection (e.g. pain when urinating, urinating more often than usual, low back or flank pain)
  • vision problems (e.g., redness, blurred vision, eye pain, severe dry eye)

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • infusion-related reactions (e.g., fever, chills, rigors, difficulty breathing, itching, severe dizziness)
  • signs of heart attack (e.g., sudden chest pain or pain radiating to back, down arm, jaw; sensation of tightness or pressure of the chest; nausea; vomiting; sweating; anxiety)
  • signs of meningitis not caused by infection (e.g., headache [severe], throbbing, or with stiff neck or back)
  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
  • signs of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)

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.

Are there any other precautions or warnings for 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.

Contact Lenses: This medication can cause severe eye irritation. Wearing contact lenses makes this irritation more likely to occur. It is recommended that you wear glasses while you are receiving treatment with cetuximab, to reduce the risk of permanently damaging your vision.

Fluid and electrolyte balance: Cetuximab may cause the levels of electrolytes such as potassium, sodium, magnesium, chloride, and calcium in the blood to change while taking this medication. If you experience symptoms of fluid and electrolyte imbalance such as muscle pains or cramps; dry mouth; numb hands, feet, or lips; or racing heartbeat, contact your doctor as soon as possible. Your doctor will do blood tests regularly to monitor the levels of these electrolytes in your blood while you are taking this medication.

Heart problems: Serious and potentially life-threatening heart problems such as heart attack and sudden death have occurred rarely in people who were using cetuximab. If you have a heart problem (e.g., arrhythmia, angina, heart failure), you will be monitored closely by your doctor during the infusion and immediately after the infusion is finished.

Kidney function: This medication may cause decreased kidney function and rarely, kidney failure. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience a decrease in urine produced or the number of times you need to urinate daily, let your doctors know as soon as possible.

Infection: As well as killing cancer cells, cetuximab can reduce the number of cells that fight infection in the body (white blood cells). This increases the risk of developing an infection or reactivating an inactive infection (e.g., herpes, shingles). If possible, avoid contact with people with contagious infections. Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of white blood cells in your blood.

Infusion-related reactions: There have been reports of severe infusion-related reactions, sometimes resulting in death, in people with who were given cetuximab. Your health care provider will closely monitor you during and after the infusion. These reactions usually occur within 30 minutes to 2 hours of starting the infusion. Your doctor will probably want you to stay at the clinic for at least one hour after the infusion is finished, to watch for signs of an infusion reaction.

If you experience symptoms of an infusion reaction, such as fever, chills, difficulty breathing, tightness of chest or throat, stomach upset, and rash, tell your health care provider immediately.

It is important to take the medication(s) recommended by your doctor before your infusion of cetuximab. If you experience a severe infusion reaction, your doctor will give you additional medications to treat the reaction. Ask your doctor for more information.

Lung inflammation: Lung inflammation (interstitial lung disease), causing difficulty breathing has occurred rarely in some people taking this medication. This complication can be serious and sometimes fatal. If you experience new or worsening shortness of breath or cough (with or without fever) at any time while you are taking cetuximab contact your doctor immediately.

Skin problems: Cetuximab can cause skin disorders, such as an acne-like rash, dry and cracked skin and inflammation. These may lead to infection of the skin. If you notice cuts or sores that become inflamed and do not heal, or wounds that develop discharge, let your doctor know immediately.

This medication can also cause the skin to be more sensitive to sunlight resulting in sunburn, skin blisters, skin rash, redness, itching, or discolouration. If you experience any of these skin reactions, contact your doctor. Try to limit the length of time you are out in the sunlight or using tanning beds while you are receiving cetuximab treatment and for 2 months after your last dose of cetuximab.

Pregnancy: It is not known if cetuximab causes harm to the developing baby if it is used by the mother during pregnancy. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately. A reliable form of birth control should be used by both males and females during and for 6 months after the last dose of cetuximab.

Breast-feeding: It is not known if cetuximab passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Breast-feeding should be stopped while you are being treated with cetuximab and should not be re-started until at least 60 days after the last dose of medication.

Children: The safety and effectiveness of using this medication have not been established for children.

What other drugs could interact with this medication?

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that 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. 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.

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