Immunotherapy side effects
Immunotherapy helps your immune system fight cancer. Sometimes the immune system also attacks healthy organs, which can happen during treatment or even months after it ends.
Why it happens
Checkpoint inhibitors, such as pembrolizumab, nivolumab, atezolizumab, durvalumab, cemiplimab, and ipilimumab, can cause these side effects. They can affect the bowels (colitis), lungs (pneumonitis), thyroid, liver (hepatitis), skin, and other organs.
What helps
- Tell every doctor, nurse, dentist, and emergency room that you have had immunotherapy, even years later.
- Carry a wallet card that lists your immunotherapy drug and your oncologist's phone number.
- Report new symptoms early. Most side effects are easier to treat when caught early.
- Keep all blood test appointments, since they check your thyroid and liver.
- For mild itchy skin, use a gentle moisturizer. Call if a rash spreads, blisters, or affects your mouth.
- Do not start steroids or other medicines on your own. Your care team will guide treatment.
Call your care team right away if you have
- You have new diarrhea, belly pain, or blood or mucus in your stool (possible colitis).
- You have a new cough, chest pain, or shortness of breath (possible pneumonitis).
- You have yellow skin or eyes, dark urine, or pain in the upper right belly (possible hepatitis).
- You have extreme tiredness, headaches, a racing heart, or feel very cold or hot, or you are very thirsty and urinating a lot (possible thyroid, hormone, or blood sugar problems).
- Any other new symptom, such as muscle weakness, chest pain, a droopy eyelid, vision changes, or feeling faint. Immune side effects can affect any organ, even months after treatment ends.
Questions to ask
- Which symptoms should I call about right away?
- Who do I call after hours if I have a side effect?
- Could immunotherapy side effects happen after my treatment is finished?
Medicines that can cause this
- Atezolizumab
- Cemiplimab
- Dostarlimab
- Durvalumab
- Ipilimumab
- Nivolumab
- Nivolumab and relatlimab
- Pembrolizumab
- Tislelizumab
- Tremelimumab
Sources
Quick answers
- What is immunotherapy side effects during cancer treatment?
- Immunotherapy helps your immune system fight cancer. Sometimes the immune system also attacks healthy organs, which can happen during treatment or even months after it ends.
- Why does immunotherapy side effects happen?
- Checkpoint inhibitors, such as pembrolizumab, nivolumab, atezolizumab, durvalumab, cemiplimab, and ipilimumab, can cause these side effects. They can affect the bowels (colitis), lungs (pneumonitis), thyroid, liver (hepatitis), skin, and other organs.
- What helps with immunotherapy side effects?
- Tell every doctor, nurse, dentist, and emergency room that you have had immunotherapy, even years later; Carry a wallet card that lists your immunotherapy drug and your oncologist's phone number; Report new symptoms early. Most side effects are easier to treat when caught early; Keep all blood test appointments, since they check your thyroid and liver; For mild itchy skin, use a gentle moisturizer. Call if a rash spreads, blisters, or affects your mouth; Do not start steroids or other medicines on your own. Your care team will guide treatment.
- When should I call my care team about immunotherapy side effects?
- You have new diarrhea, belly pain, or blood or mucus in your stool (possible colitis); You have a new cough, chest pain, or shortness of breath (possible pneumonitis); You have yellow skin or eyes, dark urine, or pain in the upper right belly (possible hepatitis); You have extreme tiredness, headaches, a racing heart, or feel very cold or hot, or you are very thirsty and urinating a lot (possible thyroid, hormone, or blood sugar problems); Any other new symptom, such as muscle weakness, chest pain, a droopy eyelid, vision changes, or feeling faint. Immune side effects can affect any organ, even months after treatment ends.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.