Classification: Tyrosine Kinase Inhibitor
About: Gefitinib (Iressa®)
Gefitinib is a tyrosine kinase inhibitor. It works by targeting and blocking epidermal growth factor receptor (EGFR) tyrosine kinase. In some cancers, this receptor is overactive, causing cells to grow and divide too fast. By inhibiting EGFR, gefitinib prevents the uncontrolled growth of cells that contributes to tumor growth. Your oncology team will test your tumor for this abnormality, which must be present in order to receive the medication.
How to Take Gefitinib
Gefitinib comes as a tablet to take by mouth once daily 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. Try to take gefinitib at around the same time every day. Take the tablet whole, do not break, crush or chew. 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.
It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.
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.
The levels of this medication can also be affected by medications used to treat heartburn. Do not take proton pump inhibitors (for example, omeprazole, esomepreazole, pantoprazole, lansoprazole) while on gefitinib. If taken with an H2 receptor blocker, (ex. famoitidne, ranitidine, cimetidine), these should be taken 10 hours before or 2 hours after gefitinib. If taken with antacids (Rolaids, Tums), separate these from the gefitinib by several hours.
Storage and Handling
Store your medication in the original, labeled container at room temperature and in a dry location (unless otherwise directed by your HCP or Pharmacist). This medication should not be stored in a pillbox. Keep containers out of reach of children and pets.
If a caregiver prepares your dose for you, they should consider wearing gloves or pour the pills directly from their container into the cap, a small cup, or directly into your hand. They should avoid touching the pills. They should always wash their hands before and after giving you the medication. Pregnant or nursing women should not prepare the dose for you. 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?
Certain cancer medications, including gefitinib, are only available through specialty pharmacies. If you need to get this medication through a specialty pharmacy, your provider will help you start this process. Where you can fill your prescriptions may also be influenced by your pharmaceutical insurance coverage. Ask your health care provider or pharmacist for assistance in identifying where you can get this medication.
This medication may be covered under your prescription drug plan Depending on your diagnosis and fund availability, co-pay assistance from private foundations may be available. Patient assistance may be available to qualifying individuals, depending on your prescription drug coverage. Co-pay cards, which reduce the patent co-pay responsibility for eligible commercially (non-government sponsored) insured patients may also be 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 care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:
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.
Diarrhea can be a serious side effect that can lead to dehydration. Notify your care team if you develop diarrhea.
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.
Less common, but important side effects can include:
- 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.
- Gastrointestinal Perforation: 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). 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.
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. It is not known if gefitinib is excreted in breast milk. Due to the potential for serious adverse reactions in the nursing infant, breast-feeding while on this medication is not recommended.