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Erbitux (cetuximab)
Starting Erbitux can bring up a lot of questions, for you and for the people who love you. Here you'll find what to expect, how to feel your best day to day and where to get help, so you can focus on your life and time together.
ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.
Targeted antibody (EGFR inhibitor) · Used for: Colorectal cancer
Types and tests it may fit: KRAS G12C colorectal cancer (RAS-mutant), RAS wild-type colorectal cancer (KRAS/NRAS normal), BRAF V600E colorectal cancer
💉 Given by IV or injection · Targeted antibody (EGFR inhibitor)
The quick guide
What it is: Targeted antibody (EGFR inhibitor).
How it's given: An IV infusion in a clinic, usually once a week or every 2 weeks.
How it works: Erbitux blocks EGFR, a growth signal on cancer cells. In colorectal cancer it only helps tumors without RAS mutations (RAS wild-type), and works best for left-sided tumors. It's also combined with Braftovi for BRAF V600E and with Krazati for KRAS G12C.
Side effects you may notice, and what helps at home
| Side effect | What can help |
|---|---|
| Dermatitis (skin rash and skin changes) (Acne-like rash, dry skin, nail changes) | Thick fragrance-free moisturizer, sunscreen, gentle soap. |
| Fatigue (extreme tiredness) | Short walks and planned rest. |
| Diarrhea (loose, watery stools) | Fluids, bland food; ask your team about anti-diarrhea medicine early. |
| Low magnesium (cramps, weakness) | Tell your care team; they can help. |
Not everyone gets these. Your team may suggest other ways to manage them.
Call your care team now if you have:
- ⚠️ Boxed warning (FDA's most serious): Serious, sometimes fatal infusion reactions, and cardiopulmonary arrest. Your team monitors you closely during infusions.
- Trouble breathing, swelling, dizziness or chest tightness during or after the infusion
- Severe rash with blisters or skin infection
- New or worse cough or shortness of breath
Call 911 for trouble breathing, chest pain or signs of stroke.
🗓 What to expect
1️⃣ Before you start
- Ask your team for a written schedule and an after-hours phone number.
- Bring a list of all your medicines and supplements.
2️⃣ During each infusion
- You'll get the medicine through an IV in a clinic; nurses check you during the infusion.
- Tell the nurse right away about chills, itching, flushing or trouble breathing.
- Bring a snack, water and something to pass the time.
3️⃣ Between doses
- Watch for the side effects below and use the checklist.
- Keep up with blood tests and visits.
- Call your team for anything in the red box.
✅ Side-effect checklist
Print this and check off what you notice so you can tell your team.
| Side effect | Noticed? | Notes for my team |
|---|---|---|
| Dermatitis (skin rash and skin changes) | ☐ | |
| Fatigue (extreme tiredness) | ☐ | |
| Diarrhea (loose, watery stools) | ☐ | |
| Low magnesium (cramps, weakness) | ☐ |
Help paying for Erbitux (cetuximab)
Erbitux (cetuximab) is made by Eli Lilly.
Official manufacturer program:
- Lilly Oncology Support Center: Insurance checks, savings cards and help finding free-medicine programs for Lilly cancer medicines.
Copay cards are usually only for people with commercial (job or marketplace) insurance. If you have Medicare or Medicaid, look at free-drug programs and these independent foundations:
- PAN Foundation: Copays and coinsurance, including for people with Medicare, when a disease fund is open.
- HealthWell Foundation: Grants for copays, deductibles and premiums when a fund is open.
- CancerCare Co-Payment Assistance Foundation: Help with treatment copays for insured people under income limits.
- Good Days: Copay help and some travel costs.
- NeedyMeds: Free database of assistance programs, open to anyone.
📋 Medicare: Medicare Part B usually covers drugs given by infusion in a doctor's office or hospital outpatient clinic. You typically pay 20% after the Part B deductible. See Medicare and your cancer drugs.
More: Help from drug makers · Our guide to paying for cancer treatment.
❓ Questions you and your loved ones can ask
- What is the goal of this treatment for me?
- How will we know if it's working?
- Which side effects should I call about right away, and what number do I call after hours?
- Which medicines, vitamins or supplements should I avoid?
- Will this affect my ability to work, drive or care for my family?
- What will this cost me, and who can help me with coverage?
Support for you and your family
- Fight Colorectal Cancer: Patient guides, advocacy and community
- Colorectal Cancer Alliance: Helpline (877-422-2030) and patient navigation
- CancerCare: Free counseling, support groups and financial help
- Cancer Support Community: Support groups, a helpline and the MyLifeLine online community
Questions people often ask
How does Erbitux work?
Erbitux blocks EGFR, a growth signal on cancer cells.
How is Erbitux given?
An IV infusion in a clinic, usually once a week or every 2 weeks.
📄 The official FDA label for Erbitux (cetuximab), including its patient information section, is on DailyMed.
Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write