Medication Information Leaflet

What is this medication for?

Osimertinib is used to treat non-small cell lung cancer that may or may not have spread to other parts of the body.

Your doctor will check for a gene mutation before starting you on this.

How should I take/use this medication?

  • Take Osimertinib once a day at about the same time each day, with or without food.
  • Do not break, chew or crush the tablet. Swallow the tablet whole.
    • Inform your doctor or pharmacist if you have difficulty swallowing.

What should I do if I forget to take/use this medication?

If you forget to take a dose, take it as soon as you remember. However if it is less than 12 hours to your next dose, skip the missed dose and take your next dose at the usual time. Do not take two doses at the same time.

What precautions should I take?

Inform your healthcare professional if: 

  • You are allergic to this medication
  • You or your partner becomes pregnant or are planning for pregnancy. You should use effective birth control during treatment and for at least
    • 4 months after stopping Osimertinib (for men)
    • 6 weeks after stopping Osimertinib (for women)
  • You are breastfeeding
    • Do not breastfeed during treatment and for 2 weeks after stopping Osimertinib.
  • You have any other medical conditions such as heart problems or eye problems

What are some common side-effects of this medication?

  • Decreased appetite
    • Take small, frequent meals throughout the day.
  • Diarrhoea
    • Drink plenty of clear fluids to replace those lost (2 litres everyday).
    • Avoid oily or spicy food and milk or dairy products.
  • Skin rash (may be acne-like), dry skin, itch
    • Moisturize your skin daily.
    • Avoid too much exposure to the sun as it may make the rash worse. Use sunscreen and covered clothing if you need to be under the sun for a long period of time.
  • Nail changes – ridges (uneven surface), discolouration or redness and tenderness around the nail folds
    • Keep your nails trimmed, clean and dry.
    • Avoid contact with harsh chemicals e.g. detergent or dish-washing liquids. Wear gloves when you are doing household chores.
  • Mouth sores
    • Rinse your mouth after meals using alcohol-free mouthwash or salt water.
    • Brush your teeth with a soft toothbrush.
  • Feeling tired or lack of energy
    • Do not drive or operate machinery when you feel tired.

What are some rare but serious side-effects that I need to seek medical advice immediately?

  • Very bad diarrhoea (e.g. more than 4 times a day) that does not improve even after taking medications used to stop diarrhoea
  • Sudden onset of cough, chest pain or shortness of breath, with fever
  • Severe eye discomfort, sensitivity to light, blurred eyesight
  • Fast or abnormal heartbeat, chest pain, swelling of the hands and feet, or sudden weight gain
  • Unusual bleeding, bruising or black sticky stools
  • Fever of 38° C and above, especially with chills, pain or difficulty in passing urine

The symptoms of a drug allergy include one or more of the following: 

  • Swollen face/eyes/lips/tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body

If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

What food or medication should I avoid when I take this medication?

Avoid taking grapefruit when you are taking this medication as grapefruit may interact with your Osimertinib and increase the risk of side-effects.

Inform your healthcare professional if you are taking or intend to take any other medication, supplements, traditional medications or herbal remedies. Some of these may affect how Osimertinib works. 

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children. 

How should I throw away this medication safely?

Pack Osimertinib into a bag and bring it back to the pharmacy where you received it from.

You may refer to the following website if you need more information: https://www.macmillan.org.uk/



Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.


Last updated on August 2022

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