Osimertinib (Tagrisso)

Osimertinib is a targeted cancer drug. It is pronounced oh-see-mer-tin-ib. It is also called Tagrisso.

Osimertinib is a treatment for non small cell lung cancer (NSCLC). You may have it:

  • after surgery to remove the cancer (for stage 1B to 3A lung cancer). This is called adjuvant treatment
  • as a treatment for NSCLC that has spread. This is called locally advanced or advanced (metastatic) lung cancer

How does osimertinib work?

Osimertinib is a cancer growth blocker. It blocks proteins on cancer cells that encourage the cancer to grow.

These proteins are called epidermal growth factor receptors (EGFR). If you have a cancer that has these receptors it is called EGFR positive. You have tests on your cancer cells to check for these receptors before you can have this treatment.

Osimertinib can help slow down or stop the growth of an advanced cancer for a time. After surgery, osimertinib might help stop the cancer from coming back. 

How do you have osimertinib?

Osimertinib is a tablet. You swallow it whole with a glass of water. You can take it with or without food.

If you have trouble swallowing tablets, you can stir the tablet in a small glass of water (50ml). It will break up into very small pieces which you can then drink.

You must take tablets according to the instructions your doctor or pharmacist gives you.

You should take the right dose, not more or less.

Talk to your healthcare team before you stop taking a cancer drug, or if you miss a dose.

How often do you take osimertinib?

You take osimertinib once a day. You take it at the same time each day.

You usually take osimertinib for as long as it is working and you don’t have too many side effects.

If you have osimertinib after surgery, you take it for up to 3 years.


You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

You also have an electrocardiogram (ECG) before starting this treatment and at times during your treatment. An ECG checks the electrical activity of the heart.

What are the side effects of osimertinib?

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, pharmacist or nurse will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects

  • your side effects aren’t getting any better

  • your side effects are getting worse

  • the side effects are affecting your daily life

Early treatment can help manage side effects better. 

Contact your advice line, doctor or nurse immediately if you have signs of infection, such as a temperature above 37.5C or below 36C, or if you develop a severe skin reaction. Signs of a severe skin reaction include peeling or blistering of the skin.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Increased risk of getting an infection

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, headaches, feeling cold and shivery and generally unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection. 

Bruising, bleeding gums or nose bleeds

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae).


Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a stoma, you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables. 

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.

Skin changes

Skin problems include a skin rash, dry skin and itching. This usually goes back to normal when your treatment finishes. Your healthcare team can tell you what products you can use on your skin to help.

Less commonly, you may get hives (urticaria). Or rarely, a rash that has a ring around a central blister or crusted area (looks like a target or ‘bulls-eye’). This is called erythema multiforme.

Even more rarely, you may develop a severe skin reaction that may start as tender red patches which leads to peeling or blistering of the skin. You might also feel feverish and your eyes may be more sensitive to light (Stevens-Johnson syndrome). This is serious and could be life threatening.

Nail problems, including swelling around the nails (paronychia)

Your nails may become brittle, dry, painful, change colour or develop ridges. This usually goes back to normal when you finish treatment.

The skin around your nail might get swollen, red, and sore (paronychia). It may also become infected. Talk to the team looking after you if you notice this. 

Sore mouth

Mouth sores and ulcers can be painful. It helps to keep your mouth and teeth clean, drink plenty of fluids, avoid acidic foods such as oranges, lemons and grapefruits, and chew gum to keep the mouth moist. Tell your doctor or nurse if you have ulcers or it’s painful to swallow.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

  • an increase in the level of creatinine in the blood. It can give doctors an idea of how well the kidneys are working
  • hair thinning or complete hair loss
  • inflammation and scarring of the lung tissue – let your team know straightaway if you develop shortness of breath, a cough or high temperature
  • redness and peeling on the hands and feet (called hand-foot syndrome or palmer plantar syndrome)

Rare side effects

These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:

  • heart problems such as changes in the electrical activity of the heart (QTc prolongation) or heart failure
  • inflammation of the clear front layer of the eye (cornea) – symptoms might include pain, sensitivity to light, blurred vision, and redness
  • inflammation of the blood vessels in the skin – this can look like bruises or a rash

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do you need to know?

Other medicines, food and drink

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Pregnancy and contraception

This drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment with this drug and for at least:

  • 2 months afterwards for women
  • 4 months afterwards for men

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner becomes pregnant while having treatment.


It is not known whether this treatment affects fertility Open a glossary item in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.


It is not known whether this drug comes through into the breast milk. Doctors advise that you don’t breastfeed during this treatment.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.


Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.

You can have:

  • other vaccines, but they might not give you as much protection as usual
  • the flu vaccine (as an injection)
  • the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment

Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your immune system Open a glossary item recovers from treatment.

Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.

If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.

Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

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