Erlotinib is a targeted anticancer therapy, specifically a tyrosine kinase inhibitor (TKI) of the epidermal growth factor receptor (EGFR). It is a first-generation, reversible, small-molecule inhibitor used primarily in the treatment of non-small cell lung cancer (NSCLC) and pancreatic cancer. It selectively blocks the intracellular phosphorylation of EGFR, inhibiting tumor cell proliferation, angiogenesis, and metastasis, and promoting apoptosis. In India, it is a critical component of precision oncology for patients with EGFR mutation-positive NSCLC.
Adult: NSCLC: 150 mg orally once daily, taken on an empty stomach (at least 1 hour before or 2 hours after food). Pancreatic Cancer: 100 mg orally once daily in combination with gemcitabine.
Note: Swallow the tablet whole with a glass of water. Do not crush, chew, or split the tablet. Must be taken on an empty stomach: at least 1 hour before or 2 hours after eating. If a dose is missed, it should be taken as soon as remembered unless it is less than 12 hours until the next dose, in which case the missed dose should be skipped. Do not take two doses at the same time.
Erlotinib is a competitive, reversible inhibitor of the adenosine triphosphate (ATP) binding site on the intracellular domain of the EGFR (HER1/ErbB1). By binding to this site, it prevents autophosphorylation and subsequent activation of the downstream signaling cascades (primarily the RAS-RAF-MAPK and PI3K-AKT-mTOR pathways) that are constitutively activated in cancer cells harboring EGFR mutations.
Pregnancy: Pregnancy Category D. Erlotinib can cause fetal harm when administered to a pregnant woman. It is embryotoxic and fetotoxic in animal studies. Women of childbearing potential must use highly effective contraception during treatment and for at least 1 month after the last dose. Men with female partners of childbearing potential should use effective contraception.
Driving: Fatigue and visual disturbances (conjunctivitis, dry eyes) have been reported with erlotinib. Patients should be cautioned about driving or operating machinery if they experience these effects.
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin, Ritonavir) | Significantly increase erlotinib plasma concentrations, increasing risk of severe adverse effects. | Major |
| Strong CYP3A4 Inducers (e.g., Rifampicin, Phenytoin, Carbamazepine, St. John's Wort) | Significantly decrease erlotinib plasma concentrations, potentially leading to therapeutic failure. | Major |
| Proton Pump Inhibitors (e.g., Omeprazole, Pantoprazole) | Increase gastric pH, reducing erlotinib solubility and bioavailability by up to 50%. | Major |
| H2-Receptor Antagonists (e.g., Ranitidine, Famotidine) | Similar to PPIs; administer erlotinib at least 2 hours before or 10 hours after H2 antagonist. | Major |
| Antacids (e.g., Aluminum/Magnesium hydroxide) | Decrease erlotinib absorption; separate administration by several hours. | Moderate |
| Warfarin | Increased risk of INR elevation and bleeding; monitor INR closely. | Moderate |
| Smoking/Nicotine | Induces CYP1A1/1A2, reducing erlotinib exposure by up to 50-60%. Dose increase to 300 mg may be considered but is not standard; smoking cessation is strongly advised. | Major |
Same composition (Erlotinib (150mg)), different brands: