Products
Lapatinib is commercially available in the form of film-coated tablets (Tyverb). It has been approved in many countries since 2007.
Structure and properties
Lapatinib (C29H26ClFN4O4S, Mr = 581.1 g/mol) is present in drugs as lapatinibditosylate monohydrate. It is a 4-aniline quinazoline that exists as a yellow powder that is sparingly soluble in water.
Effects
Lapatinib (ATC L01XE07) has antitumor and antiproliferative properties. Its effects are based on inhibition of the tyrosine kinases EGFR (epidermal growth factor receptor) and HER2 (human epidermal receptor type 2). It is also referred to as a dual EGFR/HER2 inhibitor.
Indications
For the treatment of advanced or metastatic breast cancer, when HER2 is overexpressed and in combination with capecitabine (prodrug of 5-fluorouracil).
Dosage
According to the SmPC. Tablets are taken once daily at least one hour before or at least one hour after a light meal. The drug should not be administered together with grapefruit juice.
Contraindications
- Hypersensitivity
For complete precautions, see the drug label.
Interactions
Lapatinib has potential for drug-drug interactions. It is a substrate of CYP3A4 and inhibits CYP3A4, CYP2C8, BCRP, P-glycoprotein, and OATP1B1. Its release in the stomach is dependent on pH.
Adverse effects
The most common possible adverse effects include digestive discomfort, rash, hand-foot syndrome, dry skin, insomnia, fatigue, mucosal inflammation, and pain in the limbs and back.
