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Iressa Dosage

Generic name: GEFITINIB 250mg
Dosage form: tablet, coated
Drug class: EGFR inhibitors

Medically reviewed by Last updated on Feb 28, 2023.

Patient Selection

Select patients for the first-line treatment of metastatic NSCLC with IRESSA based on the presence of EGFR exon 19 deletions or exon 21 L858R mutations in their tumor or plasma specimens [see Indications and Usage (1), Clinical Studies (14)]. If these mutations are not detected in a plasma specimen, test tumor tissue if feasible.

Information on FDA-approved tests for the detection of EGFR mutations in NSCLC is available at:

Recommended Dose

The recommended dose of IRESSA is 250 mg orally once daily with or without food until disease progression or unacceptable toxicity.

Do not take a missed dose within 12 hours of the next dose.

Administration to Patients Who Have Difficulty Swallowing Solids

Immerse IRESSA tablets in 4 to 8 ounces of water by dropping the tablet in water, and stir for approximately 15 minutes. Immediately drink the liquid or administer through a naso-gastric tube. Rinse the container with 4 to 8 ounces of water and immediately drink or administer through the naso-gastric tube.

Dose Modification

Dose Modifications for Adverse Drug Reactions

Withhold IRESSA (for up to 14 days) for any of the following:

Acute onset or worsening of pulmonary symptoms (dyspnea, cough, fever) [see Warnings and Precautions (5.1)]
NCI CTCAE Grade 2 or higher in ALT and/or AST elevations [see Warnings and Precautions (5.2)]
NCI CTCAE Grade 3 or higher diarrhea [see Warnings and Precautions (5.4)]
Signs and symptoms of severe or worsening ocular disorders including keratitis [see Warnings and Precautions (5.5)]
NCI CTCAE Grade 3 or higher skin reactions [see Warnings and Precautions (5.6)]

Resume treatment with IRESSA when the adverse reaction fully resolves or improves to NCI CTCAE Grade 1.

Permanently discontinue IRESSA for:

Confirmed interstitial lung disease (ILD) [see Warnings and Precautions (5.1)]
Severe hepatic impairment [see Warnings and Precautions (5.2)]
Gastrointestinal perforation [see Warnings and Precautions (5.3)]
Persistent ulcerative keratitis [see Warnings and Precautions (5.5)]

Dose Modifications for Drug Interactions

Strong CYP3A4 Inducers

Increase IRESSA to 500 mg daily in the absence of severe adverse drug reaction, and resume IRESSA at 250 mg seven days after discontinuation of the strong CYP3A4 inducer [see Drug Interactions (7), Clinical Pharmacology (12.3)].

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.