TYKERB 250MG
LAPATINIB
What it does
Lapatinib is a cancer treatment medication that helps stop the growth of cancer cells.
Commonly used for: breast cancer, stomach cancer
Read more in plain English ↓Plain-language summary for general understanding - not medical advice. Always follow your pharmacist/doctor.
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Source: Pharmacy and Poisons Board · fetched 2026-01-28 20:11:10 · updated 2026-08-03 04:11:22
Drug Interactions
61Pharmacodynamic Warnings
Lapatinib appears in TABLE 9: Drugs that prolong the QT interval
Severe (4)
Lapatinib - increases exposure
Grapefruitjuiceispredictedtoincreasetheexposureto lapatinib.Avoid.oTheoretical
Lapatinib - decreases exposure
St John’s wort is predicted to decrease the exposure to lapatinib. Avoid.
Lapatinib - increases exposure
Clarithromycin is predicted to increase the exposure to lapatinib. Avoid. Also see TABLE 9 p. 1519
Pazopanib - increases exposure
Lapatinib increases the exposure to pazopanib. Avoid. Also see TABLE 9 p. 1519
Moderate (3)
Bictegravir - increases exposure
Lapatinib is predicted to increase the exposure to bictegravir. Use with caution or avoid.
Panobinostat - increases exposure
Lapatinib is predicted to increase the exposure to panobinostat. Adjust dose. Also see TABLE 9 p. 1519
The Active Metabolite Of Irinotecan - increases exposure
Lapatinib increases the exposure to the active metabolite of irinotecan. Monitor adverse effects and adjust dose.
Unknown (54)
Afatinib - increases exposure
Lapatinib is predicted to increase the exposure to afatinib.
Aliskiren - increases exposure
Lapatinibispredictedtoincreasetheexposuretoaliskiren. oTheoretical
Alpelisib - increases exposure
Lapatinibispredictedtoincreasetheexposuretoalpelisib. oTheoretical
Antihistamines,non-Sedating - increases exposure
Lapatinib is predicted to increase the exposure to antihistamines, non-sedating (fexofenadine).
Apixaban - increases exposure
Lapatinibispredictedtoincreasetheexposuretoapixaban. oTheoretical
Data from BNF 85 (British National Formulary). This is not a substitute for professional medical advice. Matched via: exact
About this medicine
Lapatinib is a cancer treatment medication that helps stop the growth of cancer cells.
What it treats
- breast cancer
- stomach cancer
How it works
It works by blocking certain proteins that help cancer cells grow and divide.
Who it's for
This medicine is for adults with specific types of cancer that have certain characteristics.
Cautions
- • Be cautious if you are taking other medications that can affect your heart rhythm.
AI-assisted summary grounded in BNF data - general information only, not medical advice. Always confirm with your pharmacist or doctor.
Clinical monograph: Lapatinib
BNF-referencedLapatinib is a targeted therapy classified as a tyrosine kinase inhibitor, primarily used in the treatment of metastatic breast cancer. It specifically targets tumors that overexpress human epidermal growth factor receptor-2 (HER2). Lapatinib is often used in combination with other therapies, such as capecitabine, particularly in patients who have previously received treatment with anthracyclines, taxanes, and trastuzumab.
Indications
- Treatment of metastatic breast cancer in patients with tumors that overexpress HER2
- First-line treatment of metastatic hormone-receptor-positive breast cancer in combination with an aromatase inhibitor after prior treatment with trastuzumab
- Advanced or metastatic breast cancer in patients who have had previous treatments with anthracyclines, taxanes, and trastuzumab
Dosage
Adults: 1.25 g once daily
Mechanism of action
Lapatinib is a 4-anilinoquinazoline kinase inhibitor that targets the intracellular tyrosine kinase domains of both epidermal growth factor receptor (HER1/EGFR) and HER2. By inhibiting these receptors, lapatinib disrupts the signals that promote tumor cell growth and proliferation, thus exerting its anti-cancer effects. It shows activity against cancer cell lines that have developed resistance to trastuzumab, indicating a non-cross-resistance mechanism.
Pharmacodynamics
Lapatinib acts by inhibiting the growth of tumor cells that are dependent on HER1 and HER2 signaling pathways. This inhibition leads to a reduction in cell proliferation and survival. It was developed specifically for solid tumors, including breast cancer, and has been found effective when used in combination with other chemotherapeutic agents, enhancing the overall therapeutic effect.
Pharmacokinetics
Lapatinib is absorbed after oral administration, but its bioavailability can be affected by food and the presence of gastric acids. It has a long half-life, allowing for once-daily dosing. Metabolism primarily occurs in the liver, predominantly via the CYP3A4 enzyme, and it exhibits significant drug-drug interactions due to its hepatic metabolism. Excretion is mainly through feces, with a minor portion eliminated via urine.
Adverse effects
- Diarrhoea
- Alopecia
- Decreased appetite
- Constipation
- Fatigue
- Nausea
- Skin reactions
- Headache
- Dizziness
- Mucositis
- Insomnia
- Anaemia
- Abnormal liver function
- Neutropenia
- Weakness
- Muscle pain
- Vomiting
- Weight increased
- Paronychia
- Taste altered
- Dyspnoea
- Epistaxis
Interactions
- Grapefruit juice: Severe (increases exposure)
- Pazopanib: Severe (increases exposure)
- St. John's Wort: Severe (decreases exposure)
- Clarithromycin: Severe (increases exposure)
- Bictegravir: Moderate (increases exposure)
- The active metabolite of irinotecan: Moderate (increases exposure)
- Panobinostat: Moderate (increases exposure)
- Afatinib: Unknown (increases exposure)
- Aliskiren: Unknown (increases exposure)
- Alpelisib: Unknown (increases exposure)
Precautions
- Monitor for severe diarrhoea
- Risk of QT-interval prolongation
- Caution in patients with electrolyte disturbances
Pregnancy
Manufacturer advises avoiding use unless potential benefits outweigh risks due to limited information available.
Breast-feeding
Discontinue breastfeeding during treatment and for 3 days after the last dose.
Storage
Store in a cool, dry place away from direct sunlight.
Formulations
- {'name': 'Lapatinib', 'strength': '250 mg', 'form': 'Tablet', 'manufacturer': 'Novartis Pharmaceuticals UK Ltd'}
AI-synthesized from BNF references - general information only, not a substitute for professional medical advice or the current BNF. Verify doses with a pharmacist.
Molecular reference: Lapatinib
PubChem CID 208908Molecular formula: C29H26ClFN4O4S
Mechanism of action
Lapatinib is a 4-anilinoquinazoline kinase inhibitor of the intracellular tyrosine kinase domains of both epidermal growth factor receptor (HER1/EGFR/ERBB1) and human epidermal growth factor receptor type 2 (HER2/ERBB2)with a dissociation half-life of ≥300 minutes. Lapatinib inhibits ERBB-driven tumor cell growth in vitro and in various animal models. An additive effect was demonstrated in an in vitro study when lapatinib and 5-florouracil (the active metabolite of capecitabine) were used in combination in the 4 tumor cell lines tested. The growth inhibitory effects of lapatinib were evaluated in trastuzumab-conditioned cell lines. Lapatinib retained significant activity against breast cancer cell lines selected for long-term growth in trastuzumab-containing medium in vitro. These in vitro findings suggest non-cross-resistance between these two agents. Lapatinib (GW572016) is a small-molecule dual inhibitor of epidermal growth factor receptor (ErbB1) and ErbB2 receptor kinase activities currently in phase III clinical trials. ... Phosphoprotein and microarray analyses /were used/ to carry out targeted pathway studies of phosphorylation and gene expression changes in human breast cancer cell lines in the presence or absence of lapatinib. Studies were done in four breast cancer cell lines, two of which were responsive and two of which were nonresponsive to lapatinib. Responsive cell lines, BT474 and SKBr3, constitutively overexpress ErbB2 and show an IC(50) of 25 or 32 nmol/L for lapatinib, respectively. In contrast, nonresponsive MDA-MB-468 and T47D cells expressed a low basal level of ErbB2 and showed IC(50) values in the micromolar range. Cells responsive to lapatinib exhibited strong differential effects on multiple genes in the AKT pathway. After 12 hr of exposure to 1.0 umol/L of lapatinib, AKT1, MAPK9, HSPCA, IRAK1, and CCND1 transcripts were down-regulated 7- to 25-fold in responsive BT474 and SKBr3 cells. In contrast, lapatinib weakly down-regulated the AKT pathway in nonresponsive breast cancer cell lines (<5-fold down-regulation of most genes in the pathway). Furthermore, the proapoptotic gene FOXO3A, which is negatively regulated by AKT, was up-regulated 7- and 25-fold in lapatinib-responsive SKBr3 and BT474 cells, respectively. Phosphorylated Akt and Akt-mediated phosphorylation of FOXO3A also decreased in responsive breast cancer cell lines exposed to lapatinib. Gene expression profiling also revealed that lapatinib stimulated the expression of estrogen and progesterone receptors and modulated the expression of genes involved in cell cycle control, glycolysis, and fatty acid metabolism. In BT474 and T47D cells, which expressed moderate basal levels of the estrogen and progesterone receptors, 1.0 micromol/L of lapatinib induced expression by 7- to 11-fold. These data provide insight into the mechanism of action of lapatinib in breast cancer cells. Lapatinib is a tyrosine kinase inhibitor which dually inhibits the growth factor receptors ErbB1 (epidermal growth factor receptor, EGFR) and ErbB2 (HER2). Lapatinib is a member of the 4-anilinoquinazoline class of kinase inhibitors. Members of this class of molecules have been shown to bind to the ATP binding site of protein kinases and compete with the ATP substrate. This blocks receptor phosphorylation and activation, preventing subsequent downstream signalling events. ErbB2 is one of four members of a family of genes encoding transmembrane receptors for growth factors, the other three being ErbB1 (EGFR or HER1), ErbB3 (HER3) and ErbB4 (HER4). There is evidence ... that induced overexpression of ErbB1 or ErbB2 receptors in cells in vitro produces phenotypes associated with oncogenic transformation, such as the ability to grow in soft agar and formation of tumors in nude mice. In vivo, overexpression of ErbB1 or ErbB2 has been reported in a variety of human tumors and has been associated with poor prognosis and reduced overall survival in patients with cancer. Several
Pharmacodynamics
Lapatinib is a small molecule and a member of the 4-anilinoquinazoline class of kinase inhibitors. An anti-cancer drug, lapatinib was developed by GlaxoSmithKline (GSK) as a treatment for solid tumours such as breast and lung cancer. It was approved by the FDA on March 13, 2007, for use in patients with advanced metastatic breast cancer in conjunction with the chemotherapy drug capecitabine.
Biological pathways
Source: PubChem (NCBI) · pathways from PathBank, Reactome, WikiPathways & PharmGKB.