Side Effects of Immunotherapy

Author: Marisa Healy, BSN, RN
Content Contributor: Allyson Distel, MPH
Last Reviewed: December 04, 2023

What is immunotherapy?

Immunotherapy is a cancer treatment that works with your body’s immune system to weaken or kill cancer cells.

What do I need to know about the side effects of immunotherapy?

Immunotherapy works differently than chemotherapy. There are many side effects linked with immunotherapy medications. In some cases, immunotherapy medications may make the immune system attack not only cancer cells but healthy cells. Some side effects are common and mild, while some can be severe or even life-threatening.

Side effects may:

  • Happen at any time during your treatment and even after your treatment is done.
  • Affect almost any part of your body, no matter where your cancer started.
  • Need to be monitored closely and sometimes you are prescribed medications to help manage these side effects.

Make sure that all of your providers have your correct medication list and that they know that you are on immunotherapy. You should talk with your care team about any history of immune disorders. These can make you more at risk of having side effects due to immunotherapy.

You and your oncology team will work together to look for side effects before, during, and after your treatment. Tell your care team as soon as you feel or notice a change in your body. Your care team will likely be able to manage and ease many side effects that you may have.

What are the most common side effects of immunotherapy?

There are many immunotherapy medications. Each one may affect your body in different ways, and at different times during your treatment. Tell your care team about all your health issues along with autoimmune issues (Crohn’s disease, lupus, rheumatoid arthritis, etc.), as these can get worse with immunotherapy.

Talk with your care team about your treatment plan so that you know about side effects you may have such as:

  • Lung problems: (Pneumonitis- inflammation of the lung) New or worsening cough, shortness of breath, having a hard time breathing, or chest pain. Call your provider right away or call 911.
  • Liver problems: (Hepatitis- inflammation of the liver) Yellowing of the skin or eyes, your urine appears dark or brown, pain in your abdomen (belly), bleeding or bruising more easily than normal, or nausea and vomiting that doesn’t go away.
  • Diarrhea / Intestinal problems: (Colitis- inflammation of the bowel) Abdominal pain, diarrhea, cramping, mucus or blood in the stool, dark or tar-like stools, fever. Diarrhea means different things to different people. Tell your healthcare team about any increase in your normal bowel patterns.
  • Bowel obstruction (block) or perforation: Abdominal pain, fever, constipation, bloating, and cramping. You should tell your healthcare team about any decrease in your normal bowel patterns.
  • Kidney problems: (Kidney inflammation (swelling) or failure) Decreased urine output, blood in the urine, swelling in the ankles, loss of appetite (hunger).
  • Skin reactions: Rash, with or without itching (pruritis), sores in your mouth, blistering or peeling skin, as these can become severe and you may need treatment with corticosteroids.
  • Brain and/or nerve problems: Headache, drooping of eyelids, double vision, trouble swallowing, weakness of arms, legs, or face, or numbness or tingling in the hands or feet should be told to your healthcare team.
  • Pancreas problems: (Pancreatitis- inflammation of the pancreas) Bloating, indigestion, fatty stools, loss of appetite, sweating, abdominal pain, and weight loss. Tell your care provider if you have any of these symptoms.
  • Eye problems: Tell your provider about any changes in vision, blurry or double vision, and eye pain or redness.
  • Hormone changes: Immune reactions can affect the pituitary, thyroid, pancreas, and adrenal glands, leading to inflammation of these glands. This can change how much of certain hormones are made. Some hormone levels can be checked with blood work. Tell your care team about any changes in how you are feeling.
    • Symptoms of hormonal changes are: headaches, nausea, vomiting, constipation, rapid heart rate, increased sweating, extreme fatigue, weakness, changes in your voice, changes in memory and concentration (focus), increased hunger or thirst, increased urination, weight gain, hair loss, dizziness, feeling cold all the time, and changes in mood or behavior (including irritability, forgetfulness, and decreased sex drive).

Most of these side effects, if caught early, are treatable. Sometimes, your provider may add a corticosteroid, which provides relief for inflamed parts of the body. Do not take any medication to treat your side effects without first speaking to your provider. If the side effects of immunotherapy become severe, it is likely that your provider will hold or change your treatment plan. Be sure to talk with your care team during and even after your treatment.

National Comprehensive Cancer Network, American Society of Clinical Oncology (2022). Understanding Immunotherapy Side Effects. Retrieved from

National Comprehensive Cancer Network (2023). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) Management of Immunotherapy-Related Toxicities. Retrieved from

National Institute of Health (2019). Immunotherapy to Treat Cancer. Retrieved from

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