What are the adverse effects of lapatinib?

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Last updated: June 21, 2025View editorial policy

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From the Guidelines

Lapatinib is associated with several adverse effects, including diarrhea, nausea, vomiting, rash, and fatigue, which are commonly reported in patients taking this medication. According to the study published in the Journal of the National Comprehensive Cancer Network 1, the most frequent side effects of lapatinib include:

  • Diarrhea (which can be severe and require antidiarrheal medications)
  • Nausea
  • Vomiting
  • Rash
  • Fatigue Additionally, lapatinib can cause:
  • Hand-foot syndrome (palmar-plantar erythrodysesthesia), causing redness, pain, and peeling of the skin on hands and feet
  • Hepatotoxicity with elevated liver enzymes, requiring regular liver function monitoring during treatment
  • Cardiac toxicity, manifesting as decreased left ventricular ejection fraction or QT interval prolongation, which necessitates baseline and periodic cardiac assessments
  • Pulmonary toxicity, though rare, can occur as interstitial lung disease It's essential to note that these side effects result from lapatinib's mechanism as a tyrosine kinase inhibitor targeting HER2 and EGFR pathways, which affects both cancer cells and normal tissues that rely on these signaling pathways. Most side effects are manageable with supportive care, dose modifications, or temporary treatment interruptions, as reported in the study 1.

From the FDA Drug Label

Lapatinib tablets may cause serious side effects, including:

  • heart problems, including decreased pumping of blood from the heart and an abnormal heartbeat
  • liver problems.
  • diarrhea.
  • lung problems
  • severe skin reactions.

Common side effects of lapatinib tablets in combination with capecitabine or letrozole include:

  • diarrhea
  • red, painful hands and feet
  • nausea
  • rash
  • vomiting
  • inflamed mouth, digestive tract and airways
  • mouth sores
  • headache
  • unusual hair loss or thinning
  • shortness of breath
  • dry skin
  • itching
  • tiredness
  • painful arms, legs and back
  • loss of appetite
  • indigestion
  • nose bleeds
  • nail disorders, such as nail bed changes, nail pain, infection and swelling of the cuticles
  • difficulty sleeping

The adverse effects of lapatinib include:

  • Cardiovascular events: heart problems, decreased pumping of blood from the heart, and abnormal heartbeat
  • Hepatic events: liver problems
  • Gastrointestinal events: diarrhea, nausea, vomiting, inflamed mouth, digestive tract and airways, and mouth sores
  • Dermatologic events: rash, red and painful hands and feet, dry skin, itching, and nail disorders
  • Respiratory events: lung problems and shortness of breath
  • Other events: headache, unusual hair loss or thinning, tiredness, painful arms, legs and back, loss of appetite, indigestion, nose bleeds, and difficulty sleeping 2 2

From the Research

Adverse Effects of Lapatinib

The adverse effects of lapatinib are well-documented in various studies. Some of the most common adverse effects include:

  • Diarrhea: This is one of the most common adverse effects of lapatinib, with a reported incidence of 57.8% in patients with cancer 3. The severity of diarrhea can range from mild to severe, and it is often managed with proactive strategies such as dose reduction and supportive care 4, 5.
  • Dermatologic adverse events: These include rash, skin rash, and other skin-related adverse events. Most of these events are mild to moderate in severity and do not require treatment intervention 4, 5.
  • Gastrointestinal adverse events: In addition to diarrhea, lapatinib can also cause other gastrointestinal adverse events such as nausea and vomiting. The reported incidence of these events is 30.8% for nausea and 19.6% for vomiting 3.
  • Cardiac toxicity: This is a rare adverse effect of lapatinib, but it can occur in some patients 5, 6.

Management of Adverse Effects

The management of adverse effects is crucial to minimize the impact of lapatinib on patients' quality of life. Some strategies for managing adverse effects include:

  • Proactive management of diarrhea: This includes dose reduction, supportive care, and education on preventive measures and ongoing surveillance 4.
  • Management of dermatologic adverse events: This includes education on the potential for adverse events and the importance of preventive measures, ongoing surveillance, and appropriate treatment 4.
  • Use of gastrointestinal protective agents: This can help to reduce the risk of gastrointestinal adverse events such as diarrhea, nausea, and vomiting 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Lapatinib side-effect management.

Clinical journal of oncology nursing, 2010

Research

Lapatinib: a sword with two edges.

Pathology oncology research : POR, 2008

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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