Gefitinib

Gefitinib is a prescription medication used to treat non-small cell lung cancer. Gefitinib belongs to a group of drugs called epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. It is thought to work by blocking the action of a certain naturally occurring substance that may be needed to help cancer cells grow and multiply. 

Gefitinib is a prescription medication used to treat a certain type of lung cancer (non-small cell lung cancer or NSCLC) that has not responded to chemotherapy.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Gefitinib may be found in some form under the following brand names:

• Iressa

The most common side effects of gefitinib therapy include:

• diarrhea
• rash
• acne
• dry skin
• nausea
• vomiting

Also eye pain, redness, and irritation have occurred in people taking gefitinib.

This is not a complete list of possible side effects. Talk to your doctor for more information.

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• anticoagulants ('blood thinners') such as warfarin (Coumadin). Gefitinib may increase the blood-thinning effects of warfarin (Coumadin) and increase the risk of bleeding.
• rifampin or phenytoin (Dilantin). You may need a higher dose of gefitinib to maintain the effectiveness of gefitinib.
• antifungals such as itraconazole (Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend). You may need a lower dose of gefitinib to prevent side effects caused by increased levels of gefitinib.
• ranitidine or cimetidine. These medicines increase gastric pH causing a reduced plasma concentration of gefitinib. This may make gefitinib less effective.
• vinorelbine. Gefitinib, when taken along with vinorelbine, may increase the possibility you will get a condition called neutropenia. This is an abnormally low count of neutrophils, white blood cells that help your immune system fight off infections.

Many other medications may interact with gefitinib, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

Serious side effects have been reported including:

• severe lung disease. Rarely, some patients have developed interstitial lung disease (ILD), or scarring of lung tissue. Some cases have been fatal. Tell your doctor if you develop symptoms such as cough, difficulty breathing, and fever.
• increased liver enzymes or liver damage. Your doctor may periodically monitor your liver function with simple blood tests. Liver disease may cause gefitinib blood levels to increase as gefitinib is cleared from the body by the liver. 

Do not take gefitinib if you are allergic to any of its ingredients.

If you regularly eat grapefruit or drink grapefruit juice, discuss this with your doctor, as it may interfere with gefitinib.

Before receiving this medication, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to gefitinib or any other medicines
• have or have ever had pulmonary fibrosis (scarring of the lungs), or liver or kidney disease
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Gefitinib falls into category D. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans, though. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

It is not known if gefitinib crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using gefitinib.

Gefitinib is a tablet to be taken by mouth, with our without food, usually once a day.

Take gefitinib at around the same time every day.

Follow the directions on your prescription label carefully and take this medicine exactly as prescribed by your doctor. 

If you miss a dose take it as soon as you remember unless it is almost time for your next dose. 

If you have difficulty swallowing tablets, you may dissolve gefitinib tablets in water. No other liquids should be used. Drop the tablet in the water, without crushing it, stir until the tablet is dispersed (approximately 10 minutes) and drink the liquid immediately. Rinse the glass with half a glass of water and drink. The liquid can also be administered through a naso-gastric tube.

Gefitinib is not available in pharmacies. You can only get gefitinib through a distribution program that has been set up by the manufacturer for people who have taken gefitinib in the past. You will need to sign a consent form before you receive any medication. You will receive your medication by mail from a specific mail order pharmacy. Ask your doctor if you have any questions about receiving your medication.

Take gefitinib exactly as prescribed by your doctor. Follow the directions carefully. Your doctor will determine the best dose for you. If you forget a dose, take it as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose. Do not take two doses at once.

The recommended daily dose of gefitinib is one 250 mg tablet with or without food.

If you take too much gefitinib contact your local Poison Control Center or seek emergency medical attention right away.

• Store at controlled room temperature 20-25°C (68-77°F).
• Keep this and all medicines out of the reach of children.