Medical Oncologist
Targeted therapy for lung cancer
Gefitinib (Iressa, Geftinat, Geftib): — Your Complete Guide
Gefitinib is a targeted therapy tablet taken once daily for non-small cell lung cancer where the tumour carries an EGFR mutation. If your oncologist has prescribed it, your molecular test has already confirmed you are eligible. This page explains what the drug does, what side effects to watch for, and how to take it safely.
Medically reviewed by Dr. Bharati Devi Gorantla, Medical Oncologist, MBBS · MD · DM (Adyar, Chennai) · ECMO · MRCP SCE (UK) · Last reviewed August 2026
- An oral tablet, not an infusion — You take gefitinib at home by mouth. There is no drip, no hospital chair, and no infusion day.
- Only works with an EGFR mutation — Without the right mutation result, this drug offers no benefit. Your oncologist will confirm the test before prescribing.
- Available as generics in India — Geftinat and Geftib contain the same active molecule as Iressa. Ask your oncologist which is available at your centre.
- Most side effects are manageable — Skin rash and loose motions are common but treatable. One rare side effect — new breathlessness — needs same-day attention.
17+
Cancer Specialists
on Panel
on Panel
96.9%
Breast Cancer
Survival Rate*
Survival Rate*
15,000+
Patients
Treated
Treated
4.8★
Google Rating
(800+ reviews)
(800+ reviews)
Gefitinib is a targeted therapy tablet for non-small cell lung cancer with an EGFR mutation. It is taken once daily at home. It blocks the signal that drives your specific cancer cells to grow. Your oncologist will have confirmed your EGFR mutation test before prescribing it.
What do the medical terms on your prescription mean?
- EGFR (Epidermal Growth Factor Receptor)
- A protein on cell surfaces that sends signals telling cells to grow. In some lung cancers, a mutation keeps this signal permanently switched on, driving uncontrolled cell division.
- EGFR mutation
- A specific change in the EGFR gene found in a proportion of non-small cell lung cancers. Gefitinib works only when this mutation is present in your tumour.
- Tyrosine kinase inhibitor (TKI)
- The class of drug gefitinib belongs to. TKIs block the chemical messenger inside the cancer cell that carries the growth signal.
- Molecular testing
- The laboratory test done on your tumour tissue or a blood sample to look for EGFR mutations. This result decides whether gefitinib is appropriate for you.
- Generic drug
- A medicine with the same active ingredient and strength as the original brand. Geftinat and Geftib are Indian generics of Iressa; the clinical effect is the same.
What should you do before and during treatment?
- Tell your team every medicine you take — including ayurvedic, herbal, and over-the-counter tablets — before your first dose.
- Tell your team if you are pregnant, trying to get pregnant, or breastfeeding.
- Mention any past or present lung problems, including tuberculosis, before you start.
- Take the tablet at the same time each day, with or without food.
- If you miss a dose, take it as soon as you remember — unless it is nearly time for the next one. Never take two doses together.
- Attend every blood test your team schedules. Gefitinib can affect the liver, and routine tests catch any change early.
- Report new breathlessness, a dry cough, or fever the same day — do not wait for your next appointment.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Interventional Radiologist
Dr. Mohammed Imran
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Get a straight answer from a specialist
45 minutes, your reports reviewed, your questions answered in plain language.
How does gefitinib work, and who is it for?
Gefitinib works by blocking the specific protein your tumour's EGFR mutation keeps permanently switched on, cutting off the signal that tells those cancer cells to divide and survive.
It is prescribed only for non-small cell lung cancer where EGFR mutation testing has confirmed the right mutation is present. In people without this mutation, the drug has no target and offers no benefit over other treatments.
Response assessments — usually CT or PET-CT scans coordinated by your team — take place at regular intervals. Many people remain on gefitinib for months to years. Over time, in a proportion of patients, the cancer develops a new mutation that allows it to grow despite the drug. Your team will monitor for this and discuss next options if it happens.
What side effects should you know about?
The most common side effects are a skin rash on the face and upper body, and loose motions. Both affect a large proportion of patients and are usually managed with creams, dietary changes, or medicines your team prescribes — without stopping gefitinib.
Dry skin, brittle nails, and mouth soreness are also reported. Ask your team about skin care and mouth rinses at your first appointment, before symptoms appear.
A rare but serious side effect is interstitial lung disease — inflammation of the lung lining. Call your team the same day or go to hospital if you develop new breathlessness, a persistent dry cough, or a fever at any point during treatment. Do not wait.
Gefitinib can also affect liver function. Your team will monitor this through regular blood tests. Most changes are mild and caught early through routine monitoring.
Explore 75 more Lung Cancer Targeted Medicines topics
Drug Deep Dive: Gefitinib (Iressa)
- Diarrhoea on Gefitinib: Home Management and Warning Signs
- Diet and Nutrition While on Gefitinib
- Fertility, Pregnancy and Contraception on Gefitinib
- Gefitinib (Iressa, Geftinat, Geftib): The Complete Patient Guide
- Gefitinib Myths: 'It's Only for Poor Patients' and Other Half-Truths
- Gefitinib Plus Chemotherapy: Does Adding Chemo Actually Help?
- Gefitinib Price in India: Brand, Generic and Monthly Cost
- Gefitinib Rash: Why It Appears in Week Two and How to Treat It
- Gefitinib Side Effects: The Complete List and Timeline
- Gefitinib Success Rate and Survival: An Honest Look at the Numbers
- Gefitinib and Antacids: The Interaction That Silently Reduces Absorption
- Gefitinib in Early-Stage vs Advanced Lung Cancer: Different Goals
- Gefitinib in Elderly Patients and Those With Other Illnesses
- Gefitinib vs Osimertinib: Making the Decision When Cost Matters
- How Does Gefitinib Work? The First-Generation EGFR Inhibitor Explained
- How Long Does Gefitinib Take to Work?
- How Long Will You Stay on Gefitinib?
- Raised Liver Enzymes on Gefitinib: What Your LFT Report Means
- T790M Testing After Gefitinib Stops Working: The Next Step Explained
- Taking Gefitinib: Food, Timing and What to Do If You Miss a Dose
- Tests and Monitoring While You Are on Gefitinib
- When Gefitinib Stops Working: Resistance and What Comes Next
- Who Is Eligible for Gefitinib? EGFR-Mutant Lung Cancer
- Will Insurance or a Government Scheme Pay for Gefitinib?
- Work, Travel and Daily Life on Gefitinib
Drug Deep Dive: Alectinib (Alecensa)
- Alectinib (Alecensa, Alectinib): The Complete Patient Guide
- Alectinib After Surgery for Early-Stage ALK-Positive Lung Cancer
- Alectinib Myths: Is ALK-Positive Cancer 'Curable'?
- Alectinib Price in India: Brand, Generic and Monthly Cost
- Alectinib Side Effects: The Complete List and Timeline
- Alectinib Success Rate and Survival: An Honest Look at the Numbers
- Alectinib and Brain Metastases: How It Protects the Brain
- Alectinib in Elderly Patients and Those With Other Illnesses
- Alectinib vs Crizotinib vs Lorlatinib: Choosing an ALK Inhibitor
- Diet and Nutrition While on Alectinib
- Do You Need Chemotherapy Alongside Alectinib?
- Drug, Food and Supplement Interactions With Alectinib
- Fertility, Pregnancy and Contraception on Alectinib
- How Does Alectinib Work? The Second-Generation ALK Inhibitor Explained
- How Long Does Alectinib Take to Work?
- How Long Will You Stay on Alectinib?
- Muscle Pain and High CPK on Alectinib: When to Worry
- Severe Sun Sensitivity on Alectinib: Preventing Serious Burns
- Taking Alectinib: Food, Timing and What to Do If You Miss a Dose
- Tests and Monitoring While You Are on Alectinib
- Weight Gain, Constipation and a Slow Pulse on Alectinib
- When Alectinib Stops Working: Resistance and What Comes Next
- Who Is Eligible for Alectinib? ALK-Positive Lung Cancer
- Will Insurance or a Government Scheme Pay for Alectinib?
- Work, Travel and Daily Life on Alectinib
Drug Deep Dive: Osimertinib (Tagrisso)
- Adjuvant Osimertinib After Lung Cancer Surgery: Three Years of Tablets
- Breathlessness or New Cough on Osimertinib: Recognising Lung Injury (ILD)
- Diet and Nutrition While on Osimertinib
- Drug, Food and Supplement Interactions With Osimertinib
- Fertility, Pregnancy and Contraception on Osimertinib
- Heart Rhythm and Ejection Fraction Changes on Osimertinib
- How Does Osimertinib Work? The Third-Generation EGFR Inhibitor Explained
- How Long Does Osimertinib Take to Work?
- How Long Will You Stay on Osimertinib?
- Osimertinib (Tagrisso): The Complete Patient Guide
- Osimertinib Myths: Clear Scans, Stopping Early and Generic Quality
- Osimertinib Price in India: Brand, Generic and Monthly Cost
- Osimertinib Side Effects: The Complete List and Timeline
- Osimertinib Success Rate and Survival: An Honest Look at the Numbers
- Osimertinib With Chemotherapy: Who Actually Benefits From the Combination?
- Osimertinib and Brain Metastases: Why It Works Inside the Brain
- Osimertinib in Elderly Patients and Those With Other Illnesses
- Osimertinib vs Gefitinib and Erlotinib: Is the Costlier Drug Worth It?
- Rash, Dry Skin and Nail Problems on Osimertinib
- Taking Osimertinib: Food, Timing and What to Do If You Miss a Dose
- Tests and Monitoring While You Are on Osimertinib
- When Osimertinib Stops Working: Resistance and What Comes Next
- Who Is Eligible for Osimertinib? EGFR-Mutant Lung Cancer
- Will Insurance or a Government Scheme Pay for Osimertinib?
- Work, Travel and Daily Life on Osimertinib
Next step
Still not sure what applies to you?
Send your reports across and a senior medical oncologist will go through what they mean, what is known, and what the options actually are.
Common questions
Frequently asked questions
What is the difference between Iressa, Geftinat, and Geftib?
All three contain gefitinib as the active ingredient at the same strength. Iressa is the original brand manufactured by AstraZeneca. Geftinat is made by Natco Pharma, and Geftib by other Indian manufacturers — both are generics approved to the same standard. Your oncologist or pharmacist will tell you which is available at your centre. The clinical effect is the same.
Do I need to take gefitinib with food?
No, gefitinib can be taken with or without food. Consistency matters more than timing — try to take it at the same time each day. If it causes stomach discomfort, a light meal alongside can help. Do not change the timing without asking your team first.
What happens if gefitinib stops working?
In a proportion of patients, the cancer eventually adapts — often through a new mutation called T790M. If your scans show the disease is progressing, your oncologist may arrange a repeat biopsy or a blood-based liquid biopsy to check for this change. A different targeted drug may then be appropriate. Resistance to one drug does not mean all options are exhausted; it is a signal to re-test and reassess.
Can I take ayurvedic or herbal medicines alongside gefitinib?
Some herbal and traditional products change the way the body processes gefitinib, which can reduce its effectiveness or raise it to a level that increases side effects. Tell your oncologist and pharmacist everything you are taking, including supplements and over-the-counter products, before you start and whenever you add something new. They will advise what is safe to continue. Never stop the gefitinib tablet on your own.
Is the skin rash a sign the drug is working?
Some research has observed an association between skin rash and treatment response in patients on EGFR inhibitors, but this cannot be applied reliably to individual cases. A rash does not confirm the drug is working for you specifically, and no rash does not mean it is not. Your response is assessed through scans, not skin changes. Report the rash to your team so it can be treated — there are effective skin care options and you should not endure it untreated.
How long will I take gefitinib?
There is no fixed duration. Most people continue as long as the drug is controlling the disease and side effects are manageable. Your team will assess response at regular intervals through imaging. Some people remain on gefitinib for several years; others need to change sooner if the cancer progresses or side effects become difficult to manage. Your oncologist will review the decision at each assessment.