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Gefitinib (Iressa®)

OncoLink Team
Last Modified: November 9, 2015

Pronounced: geh-FIT-in-ib
Classification: Tyrosine Kinase Inhibitor

About Gefitinib

Gefitinib is a medication that inhibits the activity of tyrosine kinase, an enzyme necessary for human Epidermal Growth Factor Receptor (EGFR) to function. By inhibiting this enzyme, gefitinib prevents EGFRs from promoting tumor cell growth, preventing natural cell death, and promoting angiogenesis (growth of blood vessels to feed cancer cells).

How to Take Gefitinib

Gefitinib comes as a tablet to take by mouth. It is taken once a day and can be taken with or without food. If you miss a dose, take it as soon as you remember. However, if it is less than 12 hours until your next dose, skip the dose. Do not take 2 doses at once to make up for a missed dose.

If you cannot swallow gefitinib tablets whole, you can place them in 4-8 ounces of water, stir, and allow to dissolve, which may take 15-20 minutes.  You should drink the mixture right away, add another 4-8 ounces of water to the container and drink it to be sure you’ve gotten all the medication.

The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These include: grapefruit, grapefruit juice, verapamil, ketoconazole, rifampin, phenytoin, St. John’s wort, and modafanil. Be sure to tell your healthcare provider about all medications and supplements you take. If you take warfarin (Coumadin), you should monitor your INR closely, as this medication can cause an increase in bleeding time.

You should not take gefitinib at the same time as "heartburn" medications (including proton pump inhibitors such as prilosec, nexium, protonix; H2 blockers, such as tagamet, zantac; and antacids, such as Tums, Rolaids) as these may effect how gefitinib is absorbed. If you need to take these types of medications, talk with your care provider or pharmacist about how to take them.

Storage and Handling

Store this medication at room temperature in the original container. If you prefer to use a pillbox, discuss this with your oncology pharmacist. Ask your oncology team where to return any unused medication for disposal. Do not flush down the toilet or throw in the trash.

Where do I get this medication?

Gefitinib is available through select specialty pharmacies. Your oncology team will work with your prescription drug plan to identify an in-network specialty pharmacy for distribution of this medication and shipment directly to your home. 

Insurance Information

This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals without prescription drug coverage. A savings program, which reduces the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, is also available. Your care team can help you find these resources, if they are available.

Possible Side Effects of Gefitinib

There are a number of things you can do to manage the side effects of gefitinib. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:


Diarrhea is common with this medication and can become severe. Notify your healthcare team if you have diarrhea, as they can recommend medications to help manage the diarrhea. In addition, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals and seeds. Soluble fiber is found in some foods and absorbs fluid, which can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange sections, boiled potatoes, white rice, products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses on non-alcoholic, un-caffeinated fluid a day to prevent dehydration.

Nail and Skin Changes

Gefitinib has some unique nail and skin side effects that you may develop. Patients may develop a rash. While this rash may look like acne, it is not, and should not be treated with acne medications. The rash may appear red, swollen, crusty, dry and feel sore. You may also develop very dry skin, which may crack, be itchy or become flaky or scaly. The rash typically starts in the first week of treatment, but can occur at any time during treatment. Tips for managing your skin include:

  • Use a thick, alcohol-free emollient lotion or cream on your skin at least twice a day, including right after bathing.
  • Avoid sun exposure, as it can worsen the rash or cause a severe burn. Use a sunscreen with an SPF of 30 or higher and wear a hat and sunglasses to protect your head and face from the sun.
  • Bathe/shower in cool or lukewarm (not hot) water and pat your skin dry.
  • Use soaps, lotions and laundry detergents without alcohol, perfumes or dyes.
  • Wear gloves to wash dishes or do housework or gardening.
  • Drink plenty of water and try not to scratch or rub your skin.
  • Notify your healthcare team if you develop a rash, as they can provide suggestions to manage the rash and/or prescribe a topical medication to apply to the rash or an oral medication.
  • If you develop peeling or blistering of the skin, notify your healthcare team right away.


While receiving gefitinib, you may develop an inflammation of the skin around the nail bed/cuticle areas of toes or fingers, which is called paronychia. It can appear red, swollen or pus filled. Nails may develop "ridges" in them or fall off. You may also develop cuts or cracks that look like small paper cuts in the skin on your toes, fingers or knuckles. These side effects may appear several months after starting treatment, but can last for many months after treatment stops.

  • Follow the same recommendations for your skin (above).
  • Don't bite your nails or cuticles or cut the cuticles.
  • Keep your fingernails and toenails clean and dry.
  • You may use nail polish, but do not wear fake nails.
  • Notify your doctor or nurse if any nails fall off or you develop any of these side effects or other skin abnormalities.

Eye Concerns

While receiving gefitinib, some patients may develop irritation or damage to the cornea (clear part covers the eyeball) or changes in your eyesight. Notify your healthcare team if you develop any eye pain, swelling, redness or any vision changes, including blurriness and sensitivity to light.

In addition, your eyelashes may grow very fast, become very long, and bother your eyes. This will resolve when the medication is stopped. You may need to trim your eyelashes- or have someone do it for you to prevent this from becoming irritating.

Gastrointestinal Tear

This medication can cause a tear in the intestinal wall, also called a gastrointestinal perforation. Signs of this can include: new or worsening pain in the abdomen, new abdominal swelling, chills, fever, constipation, nausea or vomiting.  If you experience any of these, contact your healthcare provider immediately or go to the emergency room.

Lung Changes

This medication may cause interstitial lung disease (a scarring and stiffening of the lung tissue). These symptoms may be very similar to lung cancer symptoms. Call your healthcare provider right away if you have any new or worsening shortness of breath, cough, wheezing, or fever.

Liver Toxicity

This medication can cause liver toxicity, which your doctor may monitor for using blood tests called liver function tests. Notify your healthcare provider if you notice yellowing of the skin or eyes, your urine appears dark or brown, or you develop pain in your abdomen, as these can be signs of liver toxicity.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment and for at least 2 weeks after treatment. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive. You should consult with your healthcare team before breastfeeding while receiving this medication.



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