[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Antineoplastic monoclonal antibodies](https://durgical.com/en/pharmacology/classes/antineoplastic-monoclonal-antibodies/) › Cetuximab

# Cetuximab

## Antineoplastic monoclonal antibodies?

Antineoplastic monoclonal antibodies

## High alert?

An error with this medicine can cause serious harm: double checks and protocols are used.

Chimeric anti-EGFR antibody for RAS wild-type colorectal cancer and head and neck cancer; typical effects: acne-like rash, low magnesium, infusion reactions.

Updated Nov 1, 2026

Also called: anti-EGFR antibody

## Quick facts

**Group**
[Antineoplastic monoclonal antibodies](https://durgical.com/en/pharmacology/classes/antineoplastic-monoclonal-antibodies/)

**Target**
Epidermal growth factor receptor (EGFR), extracellular domain III

**Used for**
Metastatic colorectal cancer

**Key effects**
Acne-like · Itching · Headache

**Monitor**
Vital signs during · Magnesium · Skin and nails

**ATC**
L01FE01

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Epidermal growth factor receptor (EGFR), extracellular domain III**Cetuximab

ⓘ The crystal shows the EGFR extracellular region with the cetuximab Fab bound to domain III, where it covers the site used by EGF.

**Target in 3D:** Epidermal growth factor receptor (EGFR), extracellular domain III. PDB structure 1YY9 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1YY9) · Drag to rotate · pinch to zoom

Cetuximab is a chimeric mouse–human IgG1 antibody against domain III of the EGFR extracellular region. It blocks the binding of EGF and other ligands, prevents receptor dimerisation and switches off the growth and survival signals of the receptor; it can also trigger antibody-dependent cellular cytotoxicity. Tumours with KRAS mutations signal downstream of the receptor and do not benefit, so RAS status is tested in colorectal cancer.

- Binds EGFR extracellular domain III
- Ligand binding and dimerisation are blocked
- Growth and survival signals stop; ADCC added
- No benefit if KRAS is mutated (signal is downstream)

## Indications

- Metastatic colorectal cancer that is KRAS (RAS) wild-type and expresses EGFR, alone or with irinotecan-based chemotherapy. [Colorectal cancer →](https://durgical.com/en/conditions/colorectal-cancer/)
- Head and neck squamous cell carcinoma: with radiotherapy for locally advanced disease, with platinum chemotherapy, or alone after platinum failure. [Head and neck squamous cell carcinoma (oral cavity and oropharynx, HPV) →](https://durgical.com/en/conditions/head-and-neck-squamous-cell-carcinoma/)

## Adverse effects

### Common

- Acne-like (acneiform) rash in most patients
- Itching, dry skin, nail changes
- Headache
- Diarrhoea
- Low magnesium

### Serious (rare, important)

- Severe infusion reactions and anaphylaxis, more frequent in people allergic to red meat or with past tick bites
- Cardiopulmonary arrest and sudden death with radiotherapy in head and neck cancer
- Interstitial lung disease
- Low magnesium, potassium and calcium

## Contraindications

- Previous severe infusion reaction to cetuximab
- Colorectal cancer with a RAS mutation (no benefit)
- Caution: coronary disease, heart failure, arrhythmia or low electrolytes

## Key interactions

**Radiotherapy (with or without platinum) in head and neck cancer**
Higher risk of cardiopulmonary arrest; electrolytes and heart status are watched.

## What is monitored

- Vital signs during and for at least one hour after each infusion
- Magnesium, potassium and calcium during and after treatment
- Skin and nails
- Cough or breathlessness (lung disease)
- RAS testing before use in colorectal cancer

## Administration and safety

- Intravenous infusion only, never as a push or bolus; the first infusion is longer than the following ones.
- Ask about red-meat allergy and tick bites before the first dose: they predict severe reactions.
- Observe the patient for at least one hour after the infusion, with anaphylaxis drugs at hand.
- Look-alike names: cetuximab is checked against other -mab antibodies (e.g. panitumumab, bevacizumab).

## Pregnancy and breastfeeding

May harm the fetus; a pregnancy test is done before starting and pregnancy is avoided during treatment and for months after; breastfeeding is avoided.

## Nursing care

- Vital signs before, during and after the infusion; stop it and call for help if wheeze, hoarseness, facial swelling or hypotension appear.
- Check magnesium and potassium results and ask about cramps or palpitations.
- Skin care: gentle cleansing, moisturiser and sun protection for the rash.
- Teaching: report new cough or breathlessness and severe rash; contraception during and after treatment.

## Pharmacokinetics

**Absorption**
Intravenous infusion; the first infusion runs longer than the following ones.

**Distribution**
Distribution close to the blood volume.

**Elimination**
Non-linear: partly removed by binding to EGFR (target-mediated clearance).

**Half-life**
About five days.

## Memory aid

Cetuximab: «the rash means it is working on EGFR»; remember «RAS first» (test before colorectal use) and «Mg last» (it wastes magnesium).

## Test yourself

Think of the answer, then tap the question to see it.

## Which molecular test must be done before cetuximab in colorectal cancer?

RAS (KRAS) mutation testing; it only helps RAS wild-type tumours.

## Which electrolyte typically falls with cetuximab?

Magnesium.

## Which history predicts a severe first-infusion reaction to cetuximab?

Allergy to red meat or past tick bites.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/cetuximab/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**High alert**
An error with this medicine can cause serious harm: double checks and protocols are used.

## Connections

## Related drugs 3

- [Erlotinib](https://durgical.com/en/pharmacology/erlotinib/)
- [Bevacizumab](https://durgical.com/en/pharmacology/bevacizumab/)
- [Trastuzumab](https://durgical.com/en/pharmacology/trastuzumab/)

## Related conditions 2

- [Colorectal cancer](https://durgical.com/en/conditions/colorectal-cancer/)
- [Head and neck squamous cell carcinoma (oral cavity and oropharynx, HPV)](https://durgical.com/en/conditions/head-and-neck-squamous-cell-carcinoma/)

[← Back to the class: Antineoplastic monoclonal antibodies](https://durgical.com/en/pharmacology/classes/antineoplastic-monoclonal-antibodies/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Cetuximab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a607041.html) (MedlinePlus (U.S. National Library of Medicine), 2021); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01FE01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/cetuximab/
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