erlotinib hydrochloride: clinical use

Prescribing considerations

• Treatment should be supervised by a clinician experienced in anticancer therapy.
• Confirm activating EGFR mutation status with a validated assay where required; consider tissue testing after a negative plasma result when feasible.
• Review smoking status, interacting medicines, hepatic and renal function, gastrointestinal risk factors and ocular history.
• Severe hepatic or renal impairment is not recommended because safety and efficacy are insufficiently established.
• Assess new pulmonary symptoms promptly and interrupt treatment while unexplained interstitial lung disease is investigated.

Contraindications and cautions

• Hypersensitivity to erlotinib or any excipient.
• The lactose-containing tablets should not be used in rare hereditary galactose intolerance, total lactase deficiency or glucose-galactose malabsorption.

Monitoring

• Periodic liver-function tests, with increased frequency in hepatic impairment or biliary obstruction.
• Renal function, hydration and serum electrolytes when diarrhoea, vomiting, poor intake or dehydration occurs.
• INR or prothrombin time during concomitant coumarin anticoagulation.
• Clinical monitoring for rash, diarrhoea, pulmonary toxicity, gastrointestinal perforation and ocular toxicity.
• Treatment response and continued clinical benefit.

Clinical pharmacology

Erlotinib is an oral EGFR/HER1 tyrosine kinase inhibitor. It is metabolised mainly by CYP3A4, with contributions from CYP1A2 and extrahepatic pathways, and eliminated predominantly as faecal metabolites. Food increases exposure, while cigarette smoking increases clearance.

Formulation and product differences

• The selected product consists of film-coated tablets distinguished by tablet engraving.
• The tablets contain lactose monohydrate and are essentially sodium-free.

Tablet

Route: Oral

Strengths: 25 mg, 100 mg, 150 mg