Erlotinib is a quinazoline derivative that selectively and reversibly inhibits the tyrosine kinase activity of the EGFR. USES: Non-Small Cell Lung Cancer Indicated for patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test receiving first-line, maintenance, or >=second-line treatment after progression following at least 1 prior chemotherapy regimen 150 mg PO qDay 1 hr before or 2 hrs after meals Continue until disease progression or unacceptable toxicity NSCLC limitations of use Not recommended for use in combination with platinum-based chemotherapy Safety and efficacy has not been evaluated as first-line treatment in patients with metastatic NSCLC whose tumors have EGFR mutations other than exon 19 deletions or exon 21 (L858R) substitution Pancreatic Cancer Indicated for first-line treatment in patients with locally advanced, unresectable, or metastatic pancreatic cancer 100 mg/day PO with gemcitabine Continue until disease progression or unacceptable toxicity. Malignant Gliomas Mechanism of Action: EGF receptor tyrosine kinase inhibitor; TKI inhibition possibly blocks angiogenesis and cellular proliferation Pharmacokinetics Absorption: 60% Bioavailability: 60% (increased by food to almost 100%) Peak Plasma Time: 4 hr Half-life: 36 hr Clearance: 24% higher in smokers Protein Bound: 93% Metabolism: primarily by CYP3A4; to a lesser extent by CYP1A2, and the extrahepatic isoform CYP1A1 Excretion: Feces 83%; urine 8% REFERENCE:www.mayoclinic.org,www.medscape.com