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Gefitinib Dosage

Medically reviewed by Last updated on Dec 13, 2021.

Applies to the following strengths: 250 mg

Usual Adult Dose for Non-Small Cell Lung Cancer

250 mg orally once a day until disease progression or unacceptable toxicity

NOTE: For patients who have difficulty swallowing tablets immerse the tablet in 4 to 8 ounces of water (noncarbonated) and stir until dispersed (about 15 minutes). Drink the liquid or administer through a nasogastric tube. Rinse the container with 4 to 8 ounces of water and drink or administer through nasogastric tube.


  • Select patients for the first-line treatment of metastatic NSCLC with this drug based on the presence of EGFR exon 19 deletions or exon 21 L858R mutations in their tumor or plasma specimens.

Use: For first-line treatment of metastatic non-small cell lung cancer (NSCLC) in patients whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test.

Renal Dose Adjustments

Mild to moderate renal impairment: No adjustment recommended.
Severe renal impairment: Data not available

Liver Dose Adjustments

Mild hepatic impairment: No adjustment recommended.
Moderate to severe hepatic impairment: Use with caution.


  • Withhold therapy in patients with worsening liver function.
  • Permanently discontinue therapy in patients with severe hepatic impairment.

Dose Adjustments

Withhold therapy for up to 14 days for the following adverse drug reactions and resume when fully resolved to Grade 1:

  • Acute onset or worsening of pulmonary symptoms (e.g., dyspnea, cough, fever)
  • Grade 2 or higher in alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) elevations
  • Grade 3 or higher diarrhea
  • Severe or worsening ocular disorders including keratitis
  • Grade 3 or higher skin reactions

Permanently discontinue therapy for:
  • Confirmed interstitial lung disease (ILD)
  • Severe hepatic impairment
  • GI perforation
  • Persistent ulcerative keratitis

Concomitant use with strong CYP450 3A4 inducers:
  • Avoid concomitant use if possible.
  • If concomitant use is required, increase dose to 500 mg orally once a day (in the absence of severe adverse drug reaction); resume at 250 mg dose 7 days after discontinuation of the strong CYP450 3A4 inducer.

Concomitant use with proton-pump inhibitor/H2 receptor antagonist/antacid:
  • Avoid concomitant use if possible.
  • If concomitant use is required, take this drug 12 hours after the last dose of the proton-pump inhibitor or 12 hours before the next dose of the proton-pump inhibitor.
  • Take this drug 6 hours after the last dose of the H2-receptor antagonist or antacid, or 6 hours before the next dose of the H2-receptor antagonist or antacid.



Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.


Data not available

Other Comments

Administration Advice:

  • Therapy should be initiated and supervised by a physician experienced in the use of anticancer therapies.
  • This drug should be taken at about the same time each day, with or without food.
  • A missed dose should not be taken within 12 hours of the next dose.

Storage Requirements:
  • Store in the original package to protect from moisture.

  • Hepatic: Liver function testing (periodically during therapy)
  • Gastrointestinal: Urea, electrolytes, serum creatinine (in patients at high risk of dehydration)
  • Hematologic: INR and PT (in patients concurrently taking warfarin)
  • Ocular: Signs/symptoms of ocular disorder (e.g., acute/worsening eye inflammation, lacrimation, light sensitivity, blurred vision, eye pain, red eye)
  • Respiratory: Acute onset or worsening of ILD-like symptoms (e.g., dyspnea, cough, fever)

Patient Advice:
  • If you take a proton pump inhibitor (PPI), H2 blocker, or antacid medication, talk to your healthcare provider about the best time to take it during therapy with this drug.
  • If you miss a dose and it is LESS than 12 hours until your next dose, skip the missed dose; otherwise, take the missed dose as soon as you remember. Do not take a double dose (2 doses at the same time) to make up for a forgotten dose.
  • If you have difficulty swallowing solids, talk to your healthcare provider for special instructions on how to take this drug tablet.
  • This drug may cause side effects such as unusual physical weakness that can affect your ability to perform certain activities; avoid driving and activities such as operating machinery until you know how this drug affects you.

Further information

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