Osimertinib (Tagrisso®)

Osimertinib comes as tablets. This means you can take it at home. 

During treatment you usually see a:

• cancer doctor 
• cancer nurse or specialist nurse 
• specialist pharmacist. 

This is who we mean when we mention doctor, nurse or pharmacist in this information.

You will have regular blood tests before and during treatment. A nurse or person trained to take blood (phlebotomist) will take a blood sample from you to check that it is safe for you to have treatment. 

Your doctor, nurse or pharmacist will discuss your treatment plan with you.

You usually continue to take osimertinib for as long as it is working for you and side effects can be managed. Do not stop taking it without your doctor’s advice.

You take osimertinib once a day. Your doctor, nurse or pharmacist will tell you how many tablets to take. Always take them exactly as you are told to. This is important to make sure they work as well as possible for you. 

Osimertinib can be taken with or without food. You should try to take your tablets at the same time each day. Swallow them whole with water. Do not chew, break or crush them.  

If you cannot swallow the tablets, you can dissolve them in a small amount of water. Drop them into 50ml of water and stir until they dissolve. Drink this straight away. Half-fill the glass with water again and drink this too. 

If you forget to take your tablets, do not take a double dose. If there are more than 12 hours until your next dose, take your tablets as soon as you remember. 

If there are less than 12 hours until your next dose, do not take any tablets. Take your next dose at the usual time and let your doctor or nurse know.

Other things to remember about your tablets:

• Keep them safe, somewhere that children cannot see or reach them.
• Keep them in the original package and at room temperature, away from moisture, heat and direct sunlight.
• It is important to get a new prescription before you run out of tablets or capsules. Make sure you have plenty for holidays. 
• If you are sick just after taking the tablets, contact the hospital. Do not take another dose.
• If your treatment is stopped, return any unused tablets to the pharmacist

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If your white blood cell count is low, you may be more likely to get an infection. A low white blood cell count is called neutropenia.

An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. If you have any of the following symptoms, contact the hospital straight away on the 24-hour number:

• a temperature above 37.5°C 
• a temperature below 36°C
• you feel unwell, even with a normal temperature
• you have symptoms of an infection.

Symptoms of an infection include:

• feeling shivery and shaking
• a sore throat
• a cough
• breathlessness
• diarrhoea
• needing to pass urine (pee) often, or discomfort when you pass urine.

It is important to follow any specific advice your cancer treatment team gives you.

You will have regular blood tests during treatment. If your white blood cell count is low, your doctor may stop your treatment for a short time, until your cell count increases. Sometimes they will reduce the dose of your treatment.

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.

If the number of platelets is low, you may bruise or bleed easily. You may have:

• nosebleeds
• bleeding gums
• heavy periods
• blood in your urine (pee) or stools (poo)
• tiny red, brown or purple spots that may look like a rash – these spots can be harder to see if you have black or brown skin. 

If you have any unexplained bruising or bleeding, contact the hospital straight away on the 24-hour number. You may need a drip to give you extra platelets. This is called a platelet transfusion.

This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. You may also have stomach cramps. If you have a stoma, it may be more active than usual. 

If you are passing loose stools 3 or more times a day and this is not normal for you, contact the hospital as soon as possible on the 24-hour number. Follow the advice they give you about:

• taking anti-diarrhoea medicines 
• drinking enough fluids to keep you hydrated and to replace lost salts and minerals
• any changes to your diet that might help. 

They might also ask you for a specimen of your stool to check for infection.

This treatment can cause a rash and a dry skin. Usually this is mild. Sometimes this can be itchy. Tell your doctor or nurse if you have any skin changes. They can give you advice, creams and drugs to help.

Very rarely, a much more serious skin condition can develop. You may have a skin rash which then blisters, and your skin can peel. You may also feel unwell with flu-like symptoms, such as a high temperature and joint pain. If you have any of these symptoms, contact your doctor or hospital immediately.

You may notice changes to your nails. They may:

• become brittle
• break easily
• become infected. 

Wear gloves when washing dishes or using detergents to help protect your hands and nails. Dry your hands carefully after washing. If the area around your nails becomes red, hot or swollen, tell your doctor straight away. They can give you advice and treatment to help.

You may get a sore mouth or mouth ulcers. This is usually mild, but can make you more likely to get a mouth infection. Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.

If your mouth is sore:

• tell your nurse or doctor – they can give you a mouthwash or medicines to help
• try to drink plenty of fluids
• avoid alcohol, tobacco, and foods that irritate your mouth.

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

• throbbing pain or swelling in a leg or arm
• reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
• suddenly feeling breathless or coughing.

Always call 999 if you have:

• chest pain
• difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

• medicines you have been prescribed
• medicines you buy in a shop, pharmacy or online
• vitamins or supplements 
• herbal drugs and complementary or homeopathic therapies
• recreational drugs – for example, cannabis.

Doctors usually recommend that people with cancer have vaccinations for flu and for coronavirus (covid). These help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.

If your immune system is weak, you should not have live vaccinations. Live vaccines can make you unwell because they contain a very weak version of the illness they will protect you against. Live vaccines include Zostavax^®, which is a shingles vaccine, and the yellow fever vaccine.

It is important to ask your doctor, nurse or pharmacist for advice about having vaccinations. They can explain what vaccines are right for you and when it is best to have them.

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

If you take the contraceptive pill, it may not be as effective while you are taking osimertinib.

You are advised not to breastfeed while having this treatment, or for some time after treatment ends. This is because the drugs could be passed to the baby through breast milk. 

Your doctor, nurse or pharmacist can give you more information.

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.