Products
Gefitinib is commercially available in the form of film-coated tablets (Iressa). It was approved in many countries in 2011.
Structure
Gefitinib (C22H24ClFN4O3, Mr = 446.9 g/mol) is a morpholine and aniline quinazoline derivative. It exists as a white powder that is sparingly soluble in water, especially at high pH.
Effects
Gefitinib (ATC L01XE02) is cytostatic and cytotoxic. Its effects are due to selective inhibition of the tyrosine kinase of the epidermal growth factor receptor EGFR. EGFR is proliferated on the surface of cancer cells. Inhibition of tyrosine kinase kills the cells.
Indications
For the treatment of patients with locally advanced or metastatic non-small cell lung cancer with activating EGFR mutation.
Dosage
According to the SmPC. The drug is taken once daily, independent of meals. High pH in the stomach significantly reduces bioavailability. Therefore, antacids must be administered at a time interval.
Contraindications
- Hypersensitivity
- Children
- Liver failure
- Pregnancy and lactation
Full precautions can be found in the drug label.
Interactions
Gefitinib is biotransformed by CYP3A4. Corresponding drug-drug interactions with inducers and inhibitors are clinically relevant. Gefitinib inhibits CYP2D6 and may lead to increases in CYP2D6 substrates such as metoprolol. Other interactions have been noted with antacids (see above), vitamin K antagonists, and vinorelbine.
Adverse effects
The most common potential adverse effects include digestive disturbances such as diarrhea, nausea, vomiting, inflammation of the oral mucosa, loss of appetite, weakness, and skin reactions. Other common side effects include bleeding, eye disorders, dehydration as a result of diarrhea, nail problems, hair loss, and fever. Rarely, severe side effects include hepatitis, severe skin reactions, hypersensitivity reactions, interstitial lung disease, and pancreatitis.
