What is Osimertinib used for?

non-small cell lung cancer with certain EGFR gene changes; after surgery to lower the chance the cancer comes back; after chemotherapy and radiation for lung cancer that cannot be removed with surgery.

What are the common side effects of Osimertinib?

Diarrhea. Rash or acne-like bumps. Dry, itchy skin. Nail changes, like redness or soreness around the nails. Mouth sores. Feeling tired. Lower blood counts, found on blood tests.

When should I call my care team while taking Osimertinib?

New or worse cough, shortness of breath, or chest pain, which can be a sign of lung swelling; A fast, slow, or pounding heartbeat, or feeling like you might faint; Swelling in your legs or feet, or sudden weight gain; Eye pain, red eyes, blurry vision, or new sensitivity to light; Skin that blisters or peels, or sores in your mouth, eyes, or genitals; A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher.

Osimertinib

Say it: oh-sih-MER-tih-nib · Brand names: Tagrisso

Osimertinib is a targeted pill that blocks a growth signal in lung cancers with a change in the EGFR gene.

What it is

Some lung cancers have a change in a gene called EGFR. This change sends a nonstop signal telling cancer cells to grow. Osimertinib blocks that signal, which can slow or shrink the cancer.

Often used for

non-small cell lung cancer with certain EGFR gene changes
after surgery to lower the chance the cancer comes back
after chemotherapy and radiation for lung cancer that cannot be removed with surgery

How you get it

It is a pill you take by mouth once a day, with or without food. Some people take it alone, and some take it with chemotherapy at first. Many people take it for a long time, as long as it works and side effects are OK. Your schedule may be different.

Common side effects and what helps

Diarrhea. Drink plenty of fluids and ask your team which diarrhea medicine to keep at home.
Rash or acne-like bumps. Use gentle soap and fragrance-free moisturizer.
Dry, itchy skin. Moisturize every day and take short, lukewarm showers.
Nail changes, like redness or soreness around the nails. Keep nails short and wear roomy shoes.
Mouth sores. Use a soft toothbrush and a mild salt water rinse.
Feeling tired. Rest when you need to and take short walks when you can.
Lower blood counts, found on blood tests. Your team will check them.

Call your care team right away if you have

New or worse cough, shortness of breath, or chest pain, which can be a sign of lung swelling
A fast, slow, or pounding heartbeat, or feeling like you might faint
Swelling in your legs or feet, or sudden weight gain
Eye pain, red eyes, blurry vision, or new sensitivity to light
Skin that blisters or peels, or sores in your mouth, eyes, or genitals
A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher

Before you start, tell your team

If you have heart problems, including heart failure or an irregular heartbeat
If you have had lung problems or eye problems
If you are pregnant, may become pregnant, or are breastfeeding
All the medicines, vitamins, and herbal products you take, since some can change how this medicine works

Good to know

Rarely, this medicine causes serious lung swelling. Tell your team about new breathing problems.
It can change your heart rhythm or weaken the heart. You may have heart tests, such as an ECG (a heart tracing) or an ultrasound of the heart.
You will have regular blood tests to check your blood counts and salts in your blood.
This medicine can harm an unborn baby. Ask your team about birth control during treatment and for a while after.

At home

Take it at about the same time each day.
If you cannot swallow the pill, ask your team. The label allows it to be mixed in plain water in a certain way.
If you miss a dose or throw up after a dose, ask your team what to do. Do not take an extra dose on your own.
Store the pills at room temperature in their original container, away from children and pets.
Wash your hands after touching the pills. Ask your team if others in your home should take special care.

Questions to ask

How long will I take this medicine?
What tests will I need, and how often?
Are any of my other medicines, foods, or supplements a problem with this medicine?
What should I do if I miss a dose?
Which side effects should I call you about right away, and which can wait?

Side effect guides

Sources

Quick answers

What is Osimertinib?: Osimertinib is a targeted pill that blocks a growth signal in lung cancers with a change in the EGFR gene. Brand names: Tagrisso.
What is Osimertinib used for?: non-small cell lung cancer with certain EGFR gene changes; after surgery to lower the chance the cancer comes back; after chemotherapy and radiation for lung cancer that cannot be removed with surgery.
How is Osimertinib given?: It is a pill you take by mouth once a day, with or without food. Some people take it alone, and some take it with chemotherapy at first. Many people take it for a long time, as long as it works and side effects are OK. Your schedule may be different.
What are the common side effects of Osimertinib?: Diarrhea. Rash or acne-like bumps. Dry, itchy skin. Nail changes, like redness or soreness around the nails. Mouth sores. Feeling tired. Lower blood counts, found on blood tests.
When should I call my care team while taking Osimertinib?: New or worse cough, shortness of breath, or chest pain, which can be a sign of lung swelling; A fast, slow, or pounding heartbeat, or feeling like you might faint; Swelling in your legs or feet, or sudden weight gain; Eye pain, red eyes, blurry vision, or new sensitivity to light; Skin that blisters or peels, or sores in your mouth, eyes, or genitals; A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher.

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.