Iressa

Gefitinib, the active ingredient in Iressa, is a EGFR tyrosine kinase inhibitor presented as a tablet for oral use. It treats non‑small cell lung cancer with EGFR activating mutations in adult patients.

GNH USA supplies Iressa as a licensed, GDP‑compliant international pharmaceutical supplier serving oncology centres, hospitals and pharmacies worldwide.

Gefitinib targets the EGFR pathway and is used in the management of EGFR‑mutated non‑small cell lung cancer.

First‑line therapy for EGFR‑mutated NSCLC: provides targeted inhibition of tumor growth. Second‑line therapy after chemotherapy for EGFR‑mutated NSCLC: offers an alternative targeted option. Maintenance therapy in EGFR‑mutated NSCLC: helps sustain disease control after initial response.

Gefitinib may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects: - Diarrhea: mild to moderate watery stools. - Skin rash: erythematous papular eruption, often on the face and trunk. - Nausea: occasional upset stomach. - Vomiting: intermittent episodes. - Decreased appetite: reduced food intake. - Fatigue: general tiredness.

Serious or Rare Side Effects: - Interstitial lung disease: new or worsening respiratory symptoms. - Hepatotoxicity: elevated liver enzymes or jaundice. - Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis. - QT interval prolongation: potential cardiac arrhythmia. - Ocular toxicity: visual disturbances or corneal changes. - Severe hepatic failure: signs of liver dysfunction.

Before initiating Gefitinib, clinicians should assess patient‑specific risk factors and monitor for known safety concerns.

Renal function: evaluate baseline creatinine clearance. Hepatic function: monitor liver enzymes regularly. Skin reactions: inspect for severe rash or desquamation. Pulmonary symptoms: watch for cough, dyspnea, or new infiltrates. Drug interactions: review concomitant medications for CYP3A4 modulators. Store at ambient temperature: keep in the original pack, protect from moisture and direct sunlight.

Gefitinib's pharmacokinetics can be altered by co‑administered drugs that affect CYP3A4 activity.

Major Interactions (Avoid): - Rifampin, carbamazepine, phenytoin: strong CYP3A4 inducers that may markedly reduce gefitinib exposure. - St. John’s wort: herbal CYP3A4 inducer that can lower drug levels. - Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase gefitinib concentrations and risk of toxicity.

Moderate Interactions (Monitor Closely): - Warfarin: may enhance anticoagulant effect, requiring INR monitoring. - Simvastatin: increased risk of myopathy when combined. - Systemic corticosteroids: may heighten the incidence of skin reactions.