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EGFR tyrosine-kinase inhibitor

Gefitinib (Specialist drug)

Brand names: Iressa

Gefitinib is an oral epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor used as first-line treatment of locally advanced or metastatic non-small-cell lung cancer with activating EGFR mutations.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It reversibly inhibits the tyrosine kinase activity of EGFR, blocking downstream proliferative and survival signalling in EGFR mutation-positive tumours.

Prescribing in practice

  • Interstitial lung disease can occur and may be fatal; withhold and investigate promptly if new or worsening breathlessness, cough or fever develops.
  • Use should be limited to tumours with confirmed activating EGFR mutations, under specialist oncology supervision.
  • Hepatotoxicity, diarrhoea and skin reactions are common, and concurrent CYP3A4 inducers or drugs raising gastric pH can reduce exposure.

Monitoring

Monitor liver function periodically and review for pulmonary symptoms throughout treatment.

Counselling the patient

  • Report new or worsening breathlessness, cough or fever urgently.
  • Tell the team about rash, persistent diarrhoea or eye symptoms.
  • Disclose all other medicines, including antacids and acid-suppressing treatment.

Evidence & guidelines

First-line benefit in EGFR mutation-positive NSCLC was established in the IPASS randomised controlled trial.

Reference: NICE TA192; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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