Gefitinib

Examples

Generic Name	Brand Name
gefitinib	Iressa

How It Works

Gefitinib is an epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TK) that blocks growth factors that allow some tumours to grow. Gefitinib is a medication that is taken by mouth (oral).

Why It Is Used

Gefitinib is used to shrink tumours that have progressed after initial chemotherapy treatment. This is called a third-line treatment and is used for people who have advanced disease without many treatment options. Gefitinib is used to treat non–small cell lung cancer but is currently only available for people who are already doing well on this drug.

How Well It Works

Gefitinib appears to shrink the tumour and reduce symptoms. It appears to work better in women than in men and better in non-smokers who have lung cancer.

Recent studies have shown that gefitinib may not have a long-term survival benefit for many people. Health Canada recently restricted the use of gefitinib to people with non–small cell lung cancer who are already doing well on this medicine. It is no longer prescribed for people with recently diagnosed lung cancer.¹

Side Effects

Possible serious side effects of gefitinib include:

• Allergic reactions. Signs of allergic reaction can include trouble breathing; swelling or closing of the throat; swollen face, tongue, or lips; or hives.
• Eye pain or irritation.
• Severe or ongoing nausea, vomiting, or diarrhea.
• Changes in liver function.

A rare side effect of gefitinib is interstitial lung disease, which causes shortness of breath, cough, and fever.

Less serious side effects may include:

• Mild rash or acne.
• Diarrhea.
• Nausea and vomiting (rare).
• Feeling of weakness.
• Dry skin and itching.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Gefitinib should be administered only under the supervision of a medical oncologist.

Health Canada and the U.S. Food and Drug Administration (FDA) are now recommending that gefitinib only be taken by people who are already on the drug and whose doctors believe it is helping.^{1, 2} Other drugs seem to have a better chance of helping people who have lung cancer live longer. For more information, talk to your doctor or visit http://www.hc-sc.gc.ca/dhp-mps/medeff/advisories-avis/prof/2006/iressa_3_hpc-cps_e.html.

Gefitinib can cause birth defects. Do not use this medication if you are pregnant or wish to become pregnant or father a child while you are taking it.

Do not use this medication if you have liver disease.

Be sure to tell your doctor if you are taking any of the following medications that may change the effectiveness of gefitinib:

• Itraconazole (Sporanox)
• Ketoconazole (Nizoral)
• Phenytoin (Dilantin)
• Ranitidine (Zantac) or cimetidine
• Rifampin (Rifadin)
• Warfarin (Coumadin)

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

Author:	Douglas Dana Shannon Erstad, MBA/MPH	Last Updated: August 30, 2006
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Tom Bailey, MD - Family Medicine Michael Seth Rabin, MD - Medical Oncology
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