In the U.S.—

• Antineoplastic

Gefitinib ( ge-FI-tye-nib) belongs to the group of medicines called antineoplastics. It is used to treat non-small cell lung cancer after the failure of other chemotherapy treatment.

Before you begin treatment with gefitinib, you and your doctor should talk about the good this medicine will do as well as the risks of using it.

This medicine is available only with your doctor's prescription, in the following dosage forms:

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For gefitinib, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to gefitinib.

Pregnancy—Tell your doctor if you are pregnant or if you intend to become pregnant. Studies in rats have shown that gefitinib causes miscarriages and deaths of the fetus.

Be sure that you have discussed this with your doctor before taking this medicine. It is best to use some kind of birth control while you are receiving gefitinib. Tell your doctor right away if you think you have become pregnant while receiving gefitinib.

Breast-feeding—It is not known whether gefitinib passes into the breast milk. However, gefitinib is not recommended during breast-feeding, because it may cause unwanted effects in nursing babies.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of gefitinib in children with use in other age groups.

Older adults—This medicine has been tested in elderly patients and has not been shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking gefitinib, it is especially important that your doctor and pharmacist know if you are taking any of the following:

• CYP3A4 inducers such as
• Phenytoin (e.g., Dilantin), or
• Rifampin (e.g., Rifadin)—may decreases the effectiveness of gefitinib

• Histamine H₂-receptor antagonist (medicine for ulcers), such as
• Cimetidine (e.g., Tagamet), or
• Ranitidine (e.g., Zantac )—may decrease the effectiveness of gefitinib

• Itraconazole (e.g., Sporanox) or
• Ketoconazole (e.g., Nizoral)—Higher blood levels of gefitinib may occur, increasing the chance of serious side effects

• Metoprolol (e.g., Toprol-XL, Lopressor)—Higher blood levels of metoprolol may occur

• Warfarin (e.g., Coumadin, Warfilone)—Bleeding may occur

• Idiopathic pulmonary fibrosis—Condition may worsen while receiving gefitinib therapy

• Kidney disease or
• Liver disease—The chance of serious side effects is greatly increased

Dosing—

The dose of gefitinib will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of gefitinib. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

It is very important to check with your doctor if you have diarrhea, nausea or anorexia.

It is very important to check with your doctor if you have problems breathing.

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Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• Less common
  • bloating or swelling of face, arms, hands, lower legs, or feet ;  burning, dry or itching eyes;  change in vision;  difficult or labored breathing ;  eye discharge or excessive tearing;  redness, pain, swelling of eye, eyelid, or inner lining of eyelid ;  shortness of breath;  tightness in chest;  tingling of hands or feet;  unusual weight gain or loss;  wheezing  
  
  

• Incidence unknown
  • abnormal eyelash growth;  blistering, peeling, loosening of skin;  bloating of stomach;  chills;  constipation;  cough;  darkened urine;  diarrhea;  fainting or loss of consciousness;  fast heartbeat;  fast or irregular breathing ;  fever;  indigestion;  joint or muscle pain;  large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs ;  loss of appetite;  nausea ;  pains in stomach, side, or abdomen, possibly radiating to the back;  redness, tenderness, itching, or burning of skin;  seeing floating spots before the eyes;  severe stinging of the eye;  skin rash ;  sore throat;  sores, ulcers, or white spots in mouth or on lips;  unusual tiredness or weakness;  vomiting;  yellow eyes or skin 
  
  

• Symptoms of Overdose

  Get emergency help immediately if any of the following symptoms of overdose occur

  • Diarrhea;  skin rash 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome.

• More Common
  • blemishes on the skin, pimples;  lack or loss of strength;  dry skin 
  
  

• Less common
  • irritation or soreness of mouth;  blisters under the skin, large, hard skin blisters 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.