Gefitinib

Gefitinib is an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). It blocks signaling pathways related to tumor cell proliferation, survival and metastasis by selectively inhibiting the tyrosine kinase activity of EGFR

1. Drug name

Common name: Gefitinib

2. Indications

It is used to treat patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) with sensitive mutations in the EGFR gene.

3. Specifications and properties

1. Tablet: 250mg/tablet (based on gefitinib)

2. Properties: film-coated tablets.

IV. Main ingredients

1. Active ingredient: gefitinib (epidermal growth factor receptor tyrosine kinase inhibitor)

2. Excipients: lactose, microcrystalline cellulose, croscarmellose sodium, povidone, sodium lauryl sulfate, magnesium stearate (tablet core); hypromellose, polyethylene glycol, titanium dioxide, iron oxide red (coating).

5. Usage and dosage

1. Recommended dose : 250mg (1 tablet) once a day, on an empty stomach or with food.

2. Treatment of missed doses : If you miss a dose for more than 12 hours, skip the dose for that day and take the medicine as originally planned the next day.

3. Vomiting treatment : If you vomit after taking the medicine, there is no need to take a supplementary dose. Take the next dose as originally planned.

VI. Dose adjustment

1. Hepatotoxicity :

Grade 3 ALT/AST elevation: suspend the medication until recovery to ≤ grade 1 and then reduce the dose to 125mg/day.

Grade 4 liver injury: Permanent discontinuation.

2. Interstitial lung disease (ILD) : Permanently discontinue medication after diagnosis.

7. Medication precautions

1. Medication time : It is recommended to fix the daily medication time, either on an empty stomach or after a meal.

2. Gastric acid regulator :

Avoid using it in combination with proton pump inhibitors (PPI).

H2 receptor antagonists need to be taken 6 hours apart.

3. Drug interactions :

Avoid the combined use of strong CYP3A4 inducers (such as rifampicin) or inhibitors (such as ketoconazole).

Monitor the international normalized ratio (INR) of CYP2C9 substrates such as warfarin.

8. Medication for special groups

1. Pregnant women : may cause fetal malformation, contraception is required during treatment and within 2 weeks after the last dose.

2. Lactation : Breastfeeding is prohibited during treatment and within 2 weeks after the last dose.

3. Liver insufficiency : Moderate to severe liver damage requires close monitoring.

4. Children’s : safety and effectiveness have not been established.

9. Adverse reactions

1. Common (>20%) : diarrhea (48%), rash/acne (43%), nausea (13%), vomiting (12%), fatigue (11%).

2. Serious adverse reactions :

Interstitial lung disease (ILD, incidence rate is about 1%)

Hepatotoxicity (increased ALT in about 10%)

10. Contraindications

1. It is prohibited for those allergic to gefitinib or excipients.

2. Use with caution in patients with severe hepatic insufficiency.

11. Drug interactions

1. CYP3A4 inducer/inhibitor : significantly affects the plasma concentration of gefitinib.

2. Gastric acid inhibitor : PPI can reduce the absorption rate of gefitinib by 47%.

12. Storage method

Stored below 30°C, original packaging is moisture-proof.