Lapatinib Stada (Lapatinib)

Lapatinib acts on the HER2 signaling pathway, providing targeted therapy for specific cancers.

• HER2‑positive metastatic breast cancer: improves progression‑free and overall survival.
• HER2‑positive advanced gastric cancer: delays disease progression and extends survival.
• HER2‑positive gastro‑oesophageal junction adenocarcinoma: contributes to tumor control in combination regimens.

• Lapatinib reversibly inhibits the intracellular tyrosine kinase activity of both epidermal growth factor receptor (EGFR/ErbB1) and HER2/neu (ErbB2). By blocking these receptors, it prevents downstream signaling through the MAPK and PI3K/AKT pathways, thereby reducing cellular proliferation, survival, and angiogenesis in tumor cells that overexpress HER2.

Lapatinib may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Diarrhea: frequent loose stools.
• Rash: skin redness or acne‑like eruptions.
• Nausea: feeling of sickness, sometimes with vomiting.
• Fatigue: persistent tiredness.
• Stomatitis: inflammation of the mouth lining.
• Elevated liver enzymes: mild transaminase increase.

Serious or Rare Side Effects

• Interstitial lung disease: breathing difficulties and cough.
• Severe hepatic failure: jaundice, abdominal pain, elevated bilirubin.
• Cardiac dysfunction: reduced left‑ventricular ejection fraction.
• Stevens‑Johnson syndrome: severe skin blistering.
• Severe skin reactions: toxic epidermal necrolysis.
• Hemorrhagic events: unusual bleeding or bruising.

When using Lapatinib, clinicians should observe several safety measures.

• Cardiac monitoring: assess left‑ventricular function before and during therapy.
• Liver function tests: check transaminases and bilirubin regularly.
• Dermatologic assessment: watch for severe rash or skin reactions.
• Pregnancy avoidance: drug is contraindicated; ensure effective contraception.
• Dose adjustment: consider hepatic impairment when determining dose.
• Store below 25°C: keep in the original packaging, protect from moisture and direct light.

Lapatinib can interact with other medicines, altering its effectiveness or safety.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase Lapatinib exposure.
• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce therapeutic levels.
• Antacids containing aluminum or magnesium: can decrease absorption if taken simultaneously.

Moderate Interactions (Monitor Closely)

• Warfarin: may enhance anticoagulant effect, requiring INR monitoring.
• Digoxin: potential increase in serum concentration.
• Other HER2‑targeted agents (e.g., trastuzumab): monitor for additive cardiac toxicity.