Gefzest contains Gefitinib, a tyrosine kinase inhibitor (TKI) primarily used to treat non-small cell lung cancer (NSCLC). It targets and inhibits the epidermal growth factor receptor (EGFR) tyrosine kinase, which is involved in the growth and spread of cancer cells.

Uses

Non-Small Cell Lung Cancer (NSCLC):

• Treatment of EGFR mutation-positive NSCLC in adults as first-line therapy or after prior treatment failure.

Locally Advanced or Metastatic NSCLC:

• Used for cases where standard chemotherapy may not be suitable.

Gefitinib blocks the tyrosine kinase activity of the epidermal growth factor receptor (EGFR), inhibiting signal transduction pathways involved in cell proliferation and survival of cancer cells.

Onset of Action

• The therapeutic effects may become noticeable within half an hour after initiating treatment.

Duration of Action

• The effect lasts throughout the duration of daily dosing, with steady plasma concentrations achieved within 7 to 10 days.

Dosage

• Standard Dose: 250 mg taken orally once daily, with or without food.

Common Side Effects

• Diarrhea
• Rash and acne-like skin eruptions
• Dry skin
• Nausea
• Vomiting
• Weakness
• Loss of appetite
• Stomatitis (inflammation of the mouth)

Precautions

• Liver Impairment: Monitor liver function regularly.
• Interstitial Lung Disease (ILD): Discontinue immediately if ILD is suspected.
• Pregnancy and Breastfeeding: Should be avoided; may harm the fetus or nursing baby.

Drug Interactions

• CYP3A4 inhibitors (e.g., ketoconazole): May increase Gefitinib levels.
• CYP3A4 inducers (e.g., phenytoin, rifampin): Can reduce Gefitinib efficacy.
• Antacids and Proton Pump Inhibitors: Reduce absorption of Gefitinib.

Storage

• Store at room temperature (20-25°C) in a dry place away from moisture.