Iressa

Gefitinib, the active ingredient in Iressa, is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor presented as a 250 mg tablet for oral use. It is indicated for the treatment of adult patients with non‑small cell lung cancer that harbor EGFR‑activating mutations, helping to slow tumor growth.

GNH USA supplies Iressa as a licensed, GDP‑compliant international pharmaceutical supplier serving hospitals, oncology centres, pharmacies and clinics worldwide, including both public and private healthcare networks.

Gefitinib targets EGFR‑driven non‑small cell lung cancer, an oncologic disease where EGFR mutations drive tumor growth.

- Non‑small cell lung cancer (NSCLC) with EGFR‑activating mutations: improves progression‑free survival in affected patients. - Advanced EGFR‑mutated NSCLC: delays disease progression when used as first‑line therapy. - Metastatic EGFR‑mutated NSCLC: provides a targeted oral option for patients with disseminated disease.

Gefitinib may cause a range of adverse reactions, from mild to severe.

Common Side Effects: - Diarrhea: watery stools occurring in many patients. - Rash: acne‑like skin eruptions, especially on the face and trunk. - Nausea: mild to moderate upset stomach. - Vomiting: occasional episodes of emesis. - Decreased appetite: reduced food intake. - Fatigue: generalized tiredness.

Serious or Rare Side Effects: - Interstitial lung disease: cough, dyspnea, and potentially fatal pulmonary inflammation. - Hepatotoxicity: elevated liver enzymes and possible liver failure. - Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis. - QT interval prolongation: risk of cardiac arrhythmias. - Ocular disorders: blurred vision or retinal detachment. - Severe hepatic failure: jaundice, coagulopathy, and hepatic encephalopathy.

Before initiating Gefitinib therapy, several safety considerations should be reviewed.

- Pregnancy: contraindicated (Category D) – avoid use during pregnancy. - Liver function: monitor hepatic enzymes regularly; adjust therapy if significant elevation occurs. - Skin reactions: inspect skin frequently for severe rash or desquamation. - Pulmonary health: assess for new cough or dyspnea that may signal interstitial lung disease. - Drug interactions: review concomitant CYP3A4 inhibitors or inducers. - Store at ambient temperature: keep below 25 °C, retain in the original packaging, and protect from moisture.

Gefitinib can interact with several medicines, altering its efficacy or safety.

Major Interactions (Avoid): - Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase gefitinib plasma levels. - Antacids containing aluminum or magnesium: can reduce absorption if taken simultaneously.

Moderate Interactions (Monitor Closely): - Moderate CYP3A4 inhibitors (e.g., fluconazole, erythromycin): may modestly raise drug exposure. - Warfarin: potential increase in anticoagulant effect; monitor INR. - Smoking: induces CYP1A1/1A2, potentially lowering gefitinib concentrations. - Proton pump inhibitors: may affect gastric pH and drug absorption. - Other EGFR inhibitors: concurrent use can increase toxicity risk.