[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Kinase inhibitors (targeted oncology)](https://durgical.com/en/pharmacology/classes/kinase-inhibitors/) › Afatinib # Afatinib ## Kinase inhibitors (targeted oncology)? Kinase inhibitors (targeted oncology) ## High alert? An error with this medicine can cause serious harm: double checks and protocols are used. A second-generation, irreversible inhibitor of EGFR, HER2 and HER4 for EGFR-mutant lung cancer; diarrhoea and rash are frequent and can be severe. Updated Nov 1, 2026 Also called: BIBW2992 ## Quick facts **Group** [Kinase inhibitors (targeted oncology)](https://durgical.com/en/pharmacology/classes/kinase-inhibitors/) **Target** EGFR tyrosine kinase domain **Used for** First-line treatment **Key effects** Diarrhoea · Acne-like rash · Mouth sores **Monitor** Stool frequency and hydration · Skin and nails **ATC** L01EB03 No doses: the clinician sets them by the current guideline. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Clinical What the labels mean - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## Mechanism of action ✂**EGFR tyrosine kinase domain**Afatinib ⓘ The crystal shows afatinib in the ATP pocket of the human EGFR kinase domain, where it forms a covalent bond. **Target in 3D:** EGFR tyrosine kinase domain. PDB structure 4G5J (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/4G5J) · Drag to rotate · pinch to zoom Afatinib binds covalently to the kinase domains of EGFR (ErbB1), HER2 (ErbB2) and HER4 (ErbB4) and irreversibly blocks their autophosphorylation, shutting down ErbB-family signalling. It is most active in lung tumours with non-resistant activating EGFR mutations; because it also blocks normal EGFR in skin and gut, rash and diarrhoea are common. - Enters the ATP pocket of EGFR, HER2 and HER4 - Forms a covalent, irreversible bond - ErbB autophosphorylation and signalling stop - Also hits normal EGFR: rash and diarrhoea ## Indications - First-line treatment of metastatic non-small cell lung cancer with non-resistant EGFR mutations; also squamous non-small cell lung cancer after platinum chemotherapy. [Lung cancer →](https://durgical.com/en/conditions/lung-cancer/) ## Adverse effects ### Common - Diarrhoea - Acne-like rash, dry skin, itching - Mouth sores (stomatitis) - Nail-fold inflammation (paronychia) - Decreased appetite, nausea, vomiting ### Serious (rare, important) - Severe diarrhoea with dehydration and kidney failure - Bullous and exfoliative skin reactions - Interstitial lung disease - Hepatotoxicity, sometimes fatal - Gastrointestinal perforation - Keratitis ## Contraindications - No absolute contraindications in the label ## Key interactions **P-glycoprotein inhibitors (e.g. ritonavir, verapamil, ketoconazole)** Raise afatinib exposure and toxicity. **P-glycoprotein inducers (e.g. rifampicin, carbamazepine, St John's wort)** Lower afatinib exposure. ## What is monitored - Stool frequency and hydration; kidney function and electrolytes if diarrhoea - Skin and nails - Liver tests - New cough or breathlessness - Eye pain or redness ## Administration and safety - Oral; swallowed whole at about the same time each day. - Check the name carefully: kinase inhibitors with similar «-tinib» names are not interchangeable. - Taken on an empty stomach: at least one hour before or two hours after food. ## Pregnancy and breastfeeding Can harm the fetus; effective contraception is used and breastfeeding is avoided. ## Nursing care - Make sure an antidiarrhoeal is available and the patient knows when to use it and when to call. - Check hydration, weight and kidney function if diarrhoea persists. - Inspect skin, mouth and nail folds; advise gentle skin care and sun protection. - Teaching: report severe diarrhoea, blistering rash, new breathlessness or eye pain; use contraception. ## Pharmacokinetics **Absorption** Oral; taken at least one hour before or two hours after a meal. **Distribution** Highly bound to plasma proteins. **Metabolism** Little enzymatic metabolism; it forms covalent adducts with proteins. It is a P-glycoprotein substrate. **Elimination** Mainly in the faeces. **Half-life** About 37 hours. ## Memory aid «AFAtinib grabs for good» (covalent): EGFR + HER2 + HER4. Stronger grip, stronger gut and skin toxicity. ## Test yourself Think of the answer, then tap the question to see it. ## How does afatinib's binding differ from erlotinib's? Afatinib binds covalently and irreversibly (and also blocks HER2 and HER4); erlotinib binds reversibly. ## Which transporter's inhibitors raise afatinib levels? P-glycoprotein. ## Which common afatinib effect can lead to kidney failure? Severe diarrhoea with dehydration. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/afatinib/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## What the labels mean **High alert** An error with this medicine can cause serious harm: double checks and protocols are used. ## Connections ## Related drugs 3 - [Erlotinib](https://durgical.com/en/pharmacology/erlotinib/) - [Gefitinib](https://durgical.com/en/pharmacology/gefitinib/) - [Osimertinib](https://durgical.com/en/pharmacology/osimertinib/) ## Related conditions 1 - [Lung cancer](https://durgical.com/en/conditions/lung-cancer/) [← Back to the class: Kinase inhibitors (targeted oncology)](https://durgical.com/en/pharmacology/classes/kinase-inhibitors/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [DailyMed - AFATINIB- afatinib tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ec5b9e00-3eab-4dbd-9bb3-75865b1af485) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01EB03) (WHO Collaborating Centre for Drug Statistics Methodology, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/afatinib/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/afatinib/