Gefitinib (Iressa)

Gefitinib at a glance

Gefitinib is a targeted cancer medicine taken as a tablet, usually once a day. Iressa is a verified brand; tablets are also supplied under the generic name gefitinib. It blocks a growth signal called EGFR in cancers with particular changes in that gene. Your tumour-test result is important in deciding whether this medicine is suitable.

You can take it with or without food. Unlike some oral treatments, the usual schedule has no planned week off. Skin rash and diarrhoea are common, but early advice can help keep them manageable. Blood tests and symptom reviews remain important even though you take treatment at home.

How gefitinib works

EGFR stands for epidermal growth factor receptor. It is a protein involved in sending signals that tell cells to grow and divide. Some tumours have an activating EGFR gene change, or mutation, that keeps this signal switched on. Gefitinib blocks the receptor's tyrosine kinase activity, part of the machinery that passes the signal onward.

This makes gefitinib an EGFR tyrosine kinase inhibitor, sometimes shortened to EGFR TKI. It is not conventional chemotherapy or an immune checkpoint inhibitor. However, EGFR also has roles in healthy skin and the digestive tract, which helps explain why rash, dry skin, sore mouth and diarrhoea can develop.

Treatment may shrink a tumour or slow its growth. It cannot guarantee a response, and the cancer may eventually find ways to grow despite treatment. Your team uses scans and clinical assessments to judge benefit; a rash is not a reliable personal test of whether treatment is working.

How the team decides whether it is suitable

Your oncologist considers the precise diagnosis, the EGFR result, previous treatment, other illnesses, current medicines and your priorities. Testing looks for a relevant change in the EGFR gene, not simply whether EGFR protein is present. Common sensitising changes include an exon 19 deletion and the exon 21 L858R change.

Not every EGFR alteration has the same meaning. Some make gefitinib less likely to help. The US prescribing information specifically supports the two changes above; European information describes activating EGFR mutations more broadly. Your oncologist interprets the exact result rather than treating every “EGFR-positive” report as equivalent.

Testing may use tumour tissue or tumour DNA found in blood. A negative blood result does not always exclude a mutation; testing tissue may be useful if feasible.

Existing lung disease, liver disease, severe kidney impairment or significant eye problems can affect the safety assessment.

Before treatment starts

The team reviews your symptoms, examination findings, scans and blood results. Blood tests usually include blood counts and liver and kidney function. Baseline results help distinguish a later treatment effect from a problem that was already present.

Bring every medicine you take, including indigestion remedies, vitamins and herbal products. Acid-reducing medicines deserve particular attention because they can reduce gefitinib absorption. Also mention warfarin, epilepsy medicines, tuberculosis treatment and antibiotics prescribed elsewhere.

Discuss pregnancy possibility and contraception before starting. If swallowing is difficult or you use a feeding tube, ask the pharmacist for the preparation method for your exact product. Iressa and the US generic reviewed here contain lactose; tell the team about a diagnosed rare hereditary sugar-intolerance disorder or a previous reaction to tablet ingredients.

Obtain a written diarrhoea and skin-care plan, repeat-prescription instructions and urgent contact details.

How to take gefitinib

Your daily dose

The usual adult dose is 250 mg once daily, at approximately the same time each day, with or without food. Swallow the tablet with water unless you have been taught the authorised dispersion method. Your own prescription takes priority.

There is usually no routine treatment break. Continue according to the team's plan, including weekends. The team may interrupt treatment for side effects and restart after improvement. Official guidance allows a short interruption, up to fourteen days in specified circumstances, but that is a clinician's decision rather than a pause to start yourself.

Do not halve tablets, introduce alternate-day dosing or double the dose to compensate for symptoms or an interaction. Some interactions require a specialist prescription change; simply taking more gefitinib can be harmful.

If you cannot swallow a whole tablet

Gefitinib can be dispersed into small particles in water. Have the pharmacist demonstrate the method for the dispensed product, especially if someone else will prepare it.

For European Iressa, place the intact tablet in half a glass of still drinking water. Do not crush it or use another liquid. Swirl occasionally until it disperses, which may take up to twenty minutes. Drink immediately once prepared; the product information specifies use within sixty minutes. Rinse the glass with another half-glass of water and drink that too so that you receive the full dose.

The US generic instructions reviewed here use 4–8 fluid ounces of water, approximately 120–240 mL, stirred for about fifteen minutes. Drink immediately, then rinse the container with the same amount of water and drink the rinse immediately.

European Iressa allows the dispersion through a nasogastric or gastrostomy tube; the US label specifies a nasogastric tube. Tube delivery and flushing should follow a pharmacist-approved plan for your tube and product. Do not prepare doses in advance or mix them into tube feeds yourself.

Missed doses, vomiting and storage

The European and US patient instructions say to take a forgotten dose when remembered if twelve hours or more remain before the next dose; otherwise skip it. US professional information says not to take it “within twelve hours”. At that exact boundary, follow your written plan or ask the pharmacist. Never double doses.

If you vomit after taking gefitinib, do not take another tablet to replace it. Take the next dose at the usual time. Contact the team for ongoing vomiting or difficulty keeping fluids down. If you take an extra dose accidentally, obtain medical advice immediately.

Keep tablets in their original packaging, away from moisture and out of children's reach. Follow the pack's temperature instructions; the US generic label specifies 20–25°C (68–77°F). Return unused medicine through your pharmacy rather than household waste or wastewater.

Monitoring and checking whether treatment is working

Liver function is tested periodically. Kidney tests and blood counts are usually followed too, with additional tests when diarrhoea, poor intake or other symptoms make them necessary. A person with liver cirrhosis may absorb or clear the medicine differently and needs closer assessment.

Report breathing changes promptly rather than waiting for the next scan. Likewise, painful red eyes or altered vision need an eye assessment, not just routine review. If you take warfarin, you need regular INR tests to check its blood-thinning effect because gefitinib can change the risk of bleeding.

Scans show how the cancer is responding. Symptoms, activity, appetite and treatment burden also matter. Ask when the next scan is planned and what findings would lead the team to continue, interrupt or change treatment.

If cancer grows despite gefitinib, another tumour or blood test may help identify resistance, meaning changes that allow the cancer to escape the drug's effect.

Common side effects and practical management

Side effects vary. Many skin and bowel effects begin in the first month, but new problems can develop later. Early reporting is usually more useful than waiting until symptoms become severe.

Rash, dry skin and itching

An acne-like rash can appear on the face, scalp, chest or back. It may itch or feel tender. This is a treatment-related skin reaction, not simply ordinary teenage acne. Harsh acne products may irritate the skin, so do not start them without advice.

Use gentle washing and the moisturiser recommended by your team. Protect exposed skin from sun, friction and drying products. The team may prescribe creams or an oral medicine depending on the rash. Contact them if it becomes painful, spreads rapidly, weeps or appears infected. Widespread blistering, peeling or sores involving the mouth, eyes or genitals needs emergency assessment.

Diarrhoea and dehydration

Keep track of bowel movements compared with your normal pattern. Use prescribed anti-diarrhoea treatment according to the written plan and drink regularly, taking any existing fluid restriction into account. Smaller meals may be easier while symptoms settle.

Contact the team promptly for persistent diarrhoea, worsening frequency, dizziness, very little urine or inability to drink. Severe diarrhoea can lead to dehydration and kidney problems. Blood in stools, severe pain, fever or a swollen abdomen should not be managed only by increasing anti-diarrhoea medicine. Gefitinib may need to be withheld while the cause is investigated.

Nausea, appetite changes and sore mouth

Take anti-sickness medicines as prescribed. Try smaller meals and foods you tolerate, and request dietitian support if intake or weight is falling. Persistent nausea or vomiting matters even if diarrhoea is absent because dehydration can follow.

A sore or dry mouth may make eating difficult. Gentle oral hygiene and recommended mouth care can help. Report ulcers, white patches, painful swallowing or difficulty drinking; the team can check for inflammation or infection and offer treatment.

Nail, hair and eyelash changes

Nails and the surrounding skin may become tender, inflamed or fragile. Keep nails neat, avoid picking at the skin and protect hands during tasks that cause irritation. Report pus, spreading redness or significant pain.

Hair thinning or loss can occur, and eyelashes may grow unusually or turn towards the eye. Do not try to remove troublesome eyelashes yourself. An eye specialist can help if they scratch the surface of the eye or cause discomfort.

Tiredness and weakness

Allow time for rest while keeping up gentle activity that feels manageable. Fatigue can have several causes, including the illness, poor sleep, dehydration and reduced food intake. Do not drive when weakness or fatigue makes it unsafe.

Less common but important side effects

Lung inflammation

Gefitinib can cause interstitial lung disease, or ILD: inflammation and injury within the lungs. It can be life-threatening. Symptoms include new or worsening shortness of breath, cough or fever. They can resemble infection or changes caused by the cancer, so guessing the cause at home is unsafe.

Contact the oncology service immediately for a new breathing change. Severe breathlessness requires emergency help. The prescribing guidance calls for withholding gefitinib while suspected ILD is investigated and permanently stopping it if ILD is confirmed. Obtain urgent advice before taking further doses when these symptoms arise; do not restart after a hold without instructions.

Liver injury

Raised liver enzymes are often found on routine tests. More serious liver inflammation or failure has also occurred. Urgent symptoms include yellow skin or eyes, dark urine, pale stools, pain under the right ribs or marked loss of appetite with feeling unwell.

Report these promptly. The team may interrupt treatment and repeat blood tests, or discontinue it for severe injury. Do not wait for symptoms to become obvious before attending scheduled liver tests.

Eye inflammation and corneal damage

Dry eyes or inflamed eyelids can occur, but pain, light sensitivity, redness, increased watering or blurred vision may indicate keratitis. This is inflammation of the cornea, the clear front surface of the eye. Corneal ulceration can threaten sight.

Seek prompt assessment for new or worsening eye symptoms, particularly pain or a change in vision. Avoid putting in contact lenses while an eye is painful or inflamed, and obtain advice about suitable drops. Do not use leftover steroid eye drops. Severe or worsening eye problems require treatment interruption and assessment. Under US guidance, persistent ulcerative keratitis requires permanent discontinuation.

Severe skin reactions and allergy

Rare severe reactions such as Stevens–Johnson syndrome and toxic epidermal necrolysis can cause painful blistering or peeling and sores on moist surfaces such as the mouth or eyes. These are different from the usual acne-like rash and require urgent hospital treatment. Do not take another dose while seeking emergency assessment for this type of reaction.

Sudden swelling of the lips, tongue or throat, hives with breathing difficulty or collapse may be a serious allergic reaction. Call emergency services immediately.

Bowel perforation, pancreatitis and bleeding

A hole in the stomach or bowel wall, called a perforation, has been reported. Severe or persistent abdominal pain requires urgent assessment; intense pain, collapse or a rigid abdomen is an emergency. Gefitinib is permanently discontinued when perforation occurs under US guidance.

Inflammation of the pancreas can also cause severe upper abdominal pain and vomiting. Report unexplained bleeding, including nosebleeds or blood in urine. Vomiting blood, black tar-like stools or significant bleeding with faintness needs emergency help. The team should know if you use steroids, anti-inflammatory painkillers or warfarin.

Urinary and kidney effects

Kidney blood tests or urine protein may change. Cystitis, meaning bladder inflammation, can cause burning, urgency or frequent urination; sometimes blood is present. These symptoms also have other causes, including infection. Contact the team for assessment rather than treating presumed cystitis yourself. Reduced urine after diarrhoea or vomiting can be a sign of dehydration needing prompt treatment.

Other medicines, supplements and vaccinations

Stomach-acid medicines

Gefitinib needs an acidic environment for absorption. Proton-pump inhibitors, H2 blockers and antacids can reduce how much medicine reaches the bloodstream. Tell the pharmacist about prescribed and shop-bought heartburn remedies before using them.

The US label advises avoiding proton-pump inhibitors when possible. If one is necessary, it specifies gefitinib twelve hours after the last proton-pump inhibitor dose or twelve hours before the next. For H2 blockers or antacids, it specifies six hours before or six hours after.

The European Iressa patient leaflet instead tells patients not to take antacids in the two hours before or one hour after Iressa; its professional information also warns about acid-lowering medicines more generally. These instructions differ. Use the plan agreed for your exact product and medicines, rather than choosing a shorter interval yourself. Timing may be complicated if a medicine is taken more than once daily.

Other interactions

Rifampicin, certain epilepsy medicines such as phenytoin or carbamazepine, and St John's wort can lower gefitinib exposure. Some antibiotics and antifungals can increase it. These effects involve medicine-processing enzymes such as CYP3A4; changes may require a different companion medicine, closer monitoring or a specialist prescription adjustment.

European guidance advises avoiding enzyme-inducing medicines. US information includes a supervised dose adjustment if a strong inducer is used. Do not increase gefitinib yourself. Also have antidepressants, heart medicines and all supplements checked because other enzyme pathways can matter.

Warfarin needs regular INR monitoring. Discuss vaccines with the oncology team before administration; suitability depends on the vaccine and your overall treatment, particularly for live vaccines. Do not assume every vaccine is prohibited, or arrange one without mentioning cancer treatment.

Everyday life during treatment

Many people take gefitinib at home while keeping some of their usual activities. Plan work around fatigue, bowel symptoms and skin comfort. Ensure you can reach a toilet and carry the medicines your team recommends for symptoms.

Use sun protection and gentle skin care. Tell your dentist about treatment and discuss procedures with the oncology team. Do not borrow surgery stopping rules from a different targeted medicine; obtain your own plan.

Avoid driving or machinery when weak, unusually tired, dizzy or affected by visual symptoms. Before travel, organise enough tablets, storage, prescriptions and planned blood tests. Keep treatment details and urgent contact information accessible.

Ask for help with stopping smoking, maintaining nutrition or managing anxiety when needed.

Fertility, contraception, pregnancy and breastfeeding

Gefitinib can harm an unborn baby. Tell the team before starting if you are pregnant, might be pregnant or plan a pregnancy. Contact them promptly if pregnancy occurs during treatment.

For someone who could become pregnant, the US label specifies effective contraception throughout treatment and for at least two weeks after the final dose. European information advises avoiding pregnancy during treatment without giving a fixed post-treatment interval. Confirm the method and stopping date with the team, taking account of any other medicine that requires a longer period.

The reviewed labels do not provide a specific post-treatment contraception interval for men. If you could father a pregnancy, discuss the plan rather than applying the two-week female instruction automatically.

Do not breastfeed during gefitinib treatment. Neither reviewed label gives a fixed interval after stopping, so agree when breastfeeding could safely resume with the team. Female fertility may be reduced based on animal findings; effects in people are uncertain. Discuss fertility preservation before treatment if future parenthood matters to you.

After treatment finishes

Continue follow-up until important side effects have settled and abnormal tests have been reassessed. Skin and bowel symptoms may improve after treatment stops, but persistent problems still need help. New breathing symptoms or eye problems require assessment even after the last tablet.

Keep following the agreed contraception and breastfeeding plan. Return unused tablets to the pharmacy and keep a record of when gefitinib stopped and why. If treatment is changed because the cancer has become resistant, ask whether further testing may guide the next option. Do not restart leftover tablets on your own.

Frequently asked questions