Disclaimer: This information is intended to help you understand your treatment. Always discuss your health and treatment plan with your doctor or nurse, who can answer your specific questions.
At a Glance: Quick Facts about Osimertinib
- Generic Name: Osimertinib
- Brand Name(s): The original formulation of osimertinib is Tagrisso®. As of 2025, the drug is patented and no generic is available.
- Type of Drug: Osimertinib is a type of targeted therapy. It is a tyrosine Kinase Inhibitor (TKI) targeting epithelial growth receptor (EGFR).
- How It’s Given: As a tablet to be taken by mouth (orally).
- Common Cancers Treated: Non-small cell lung cancer (NSCLC) with specific mutations in the Epidermal Growth Factor Receptor (EGFR) gene.
About Osimertinib
- What It Is and What It’s Used For: Osimertinib is a type of targeted therapy, not a traditional chemotherapy drug. It is used to treat non-small cell lung cancer that have certain abnormal changes (mutations) in a gene called EGFR. The abnormal EGFR drives the cancer cells in these patients. Your doctor will perform a test on the cancer tissue to confirm it has the specific EGFR mutation that this drug targets before prescribing it. If for some reason the test can not be done on the tumour your doctor may do a test known as liquid biopsy on the blood. It can be used after surgery to prevent cancer from returning, or to treat cancer that has spread (metastasized). It may be used alone or with chemotherapy.
- How It Works: Think of the mutated EGFR gene as a “stuck” accelerator pedal in cancer cells, constantly telling them to grow and divide. Osimertinib is designed to block the signal from this faulty EGFR protein. By cutting off this signal, it stops the cancer cells from growing and can cause them to die.
How You Will Receive This Drug
- Your Dosing Schedule: The standard dose is one tablet taken once every day. It is important to take it at around the same time each day to keep a steady level of the medicine in your body. You will likely continue taking it for as long as it is helping your condition and not causing severe side effects or as long as your doctor thinks it necessary.
- How It’s Given: Osimertinib is a tablet that you swallow whole with a glass of water. It can be taken with or without food. Do not crush, chew, or break the tablet.
- Important Instructions: If you have difficulty swallowing the tablet, you can dissolve it in a small amount of non-carbonated water (about 60 mL or 2 ounces). Stir until the tablet breaks into small pieces (it will not dissolve completely) and drink the mixture immediately. Rinse the glass with more water and drink that as well to ensure you get the full dose.
Possible Side Effects
- Most Common Side Effects:
- Diarrhea: This is very common. Your doctor may advise you on diet changes or prescribe anti-diarrhea medication.
- Skin and Nail Changes: You may develop a skin rash, dry skin, or acne. Your nails may become brittle, sore, or inflamed around the edges (paronychia).
- Sore Mouth (Stomatitis): Mild sores or inflammation in the mouth.
- Decreased Appetite.
- Fatigue: Feeling tired or weak.
- Less Common but SERIOUS Side Effects:
- Lung Problems (Interstitial Lung Disease/Pneumonitis): In rare cases, osimertinib can cause a serious and potentially life-threatening inflammation of the lungs. The symptoms can be similar to the lung cancer itself.
- Heart Problems: This can include weakening of the heart muscle (cardiomyopathy), which reduces its ability to pump blood, and changes to the heart’s electrical rhythm (QTc prolongation).
- Eye Problems (Keratitis): Inflammation of the cornea (the front of the eye) can occur.
- Low Blood Counts: It can lower your platelet count (increasing bleeding risk) and white blood cell count (increasing infection risk). This is a rare complication. it is more likely when the drug is used with chemotherapy.
- When to Contact Your Doctor Immediately:
- Signs of Lung Problems: New or worsening shortness of breath, cough, or fever.
- Signs of Heart Problems: Feeling faint, dizzy, a fluttering or irregular heartbeat, chest pain, or swelling in your ankles.
- Severe Skin Reactions: A rash that becomes painful, blistered, or starts to peel.
- Eye Problems: Blurred vision, sensitivity to light, eye pain, or redness.
- Severe Diarrhea that does not stop with medication.
Important Information to Discuss with Your Doctor
- Before You Start Treatment: Tell your doctor your full medical history, especially if you have any history of heart problems (including Long QT syndrome), electrolyte imbalances, lung problems, or eye problems.
- Pregnancy and Contraception: This drug can cause serious harm to a developing fetus.
- Women: You must use effective birth control during treatment and for at least 6 weeks after the final dose.
- Men: You must use effective contraception with a female partner during treatment and for at least 4 monthsafter the final dose.
- Drug and Food Interactions: Tell your doctor and pharmacist about all medicines you take, including prescriptions, over-the-counter drugs, vitamins, and herbal supplements. Specifically mention if you take St. John’s Wort, as it should be avoided.
Practical Tips While Taking Osimertinib
- What to Do If You Miss a Dose: If you miss a dose, take it as soon as you remember. However, if your next scheduled dose is less than 12 hours away, skip the missed dose completely and take the next one at the regular time. Contact your doctor. Do not take a double dose.
- Storage: Store the tablets at room temperature in their original container, away from moisture and direct sunlight. Keep them safely out of the reach of children and pets.
- Follow-Up and Monitoring: You will have regular appointments and blood tests to monitor your blood counts. Your doctor may also order tests to check your heart’s electrical activity (an ECG) and its pumping function (an echocardiogram).
Questions to Ask Your Healthcare Team
- What is the main goal of this treatment for my cancer?
- What are the most important signs of lung or heart problems I should watch for?
- What should I do to manage diarrhea or skin rash if they occur?
- How will you be monitoring my heart during this treatment?
- Are there any other medicines I should absolutely avoid while taking this?
- What is the number to call if I have an urgent problem after hours?