The standard usage of Gefitinib is once daily oral administration of 250mg, taken on an empty stomach or 2 hours after meals. Special populations may need to adjust their medication regimen based on liver and kidney function, pregnancy status, and other factors. The following provides detailed explanations from two aspects: standard usage and medication for special populations.

1. Standard usage and dosage

(1) Adult non-small cell lung cancer: a fixed daily dose of 250mg, taken in whole tablets, should not be crushed or chewed.

(2) Medication time: It is recommended to take it at the same time every day, on an empty stomach (1 hour before or 2 hours after meals) to optimize absorption.

(3) Course of treatment: Continue medication until disease progression or intolerable toxicity occurs, without the need to adjust dosage based on age or weight.

2. Medication for special populations

(1) Pregnancy period

Disable gefitinib. Animal studies have shown embryo fetal toxicity, and women of childbearing age need to confirm their pregnancy status before taking medication. During treatment and at least 2 weeks after discontinuing medication, they should take effective contraceptive measures.

(2) Lactation period

It is not yet clear whether the medication will enter the breast, but due to potential serious adverse reactions, breastfeeding should be stopped during the treatment period and within 2 weeks after the last administration.

(3) Liver dysfunction

Child Pugh Class C is prohibited; Mild to moderate damage (Child Pugh A/B) requires close monitoring of liver function, and medication should be suspended when ALT elevation>5-fold ULN occurs.

(4) Renal insufficiency

Mild to moderate damage (creatinine clearance rate ≥ 30mL/min) does not require dose adjustment; Serious damage or limited data on dialysis patients, caution should be exercised when using.

(5) Elderly patients

Patients aged 65 and above do not need to adjust the initial dose, but due to the increased risk of complications, it is necessary to strengthen the monitoring of adverse reactions, especially interstitial lung disease and diarrhea.

(6) Pediatric patients

The safety and efficacy of children under 18 years old have not been established and are not recommended for use.