Lapatinib: adverse event reports filed with FDA

4,544

reports as suspect product

0% of all reports · about 213 a year

57

reports, 12 months to June 2026

132 in the 12 months before

97.7%

marked serious by the reporter

70.8% across the class

11%

record death among outcomes, as reported

498 reports · not verified by FDA

Reports by month, five years

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Lapatinib reports recording the termmedian drug in kinase inhibitor

1. Diarrhoealoose or frequent stools19.1%868
2. Disease progressionthe disease advanced9.9%449
3. Neutropenialow neutrophils, a type of white blood cell8.8%401
4. Vomitingbeing sick8.8%398
5. Nauseafeeling sick8.1%369
6. Pyrexiafever7%317
7. Palmar-plantar erythrodysaesthesia syndrome6.4%293
8. Fatiguetiredness5.8%263
9. Dehydrationdehydration5.5%252
10. Astheniaweakness or lack of energy5.5%250
11. Dyspnoeashortness of breath5.3%239
12. Malignant neoplasm progression5%228
13. Metastases to central nervous system4.5%205
14. Rashskin rash4.2%191
15. Anaemialow red blood cells4%180
16. Abdominal painstomach or belly pain3.7%167
17. Febrile neutropeniafever with low white blood cells3.4%155
18. Thrombocytopenialow platelets3.3%150
19. Hypokalaemialow blood potassium3.1%139
20. Mucosal inflammation3.1%139
21. General physical health deteriorationgeneral decline in health3%135
22. Alanine aminotransferase increasedraised liver enzyme (ALT)2.8%128
23. Off label useused for a purpose or in a way not on the label2.6%118
24. Headachehead pain2.5%112
25. Drug ineffectivethe medicine did not work as expected2.4%107
26. Pleural effusionfluid around the lung2.3%106
27. Deaththe patient died; cause not stated by this term2.3%104
28. Breast cancer metastatic2.3%103
29. Dizzinesslight-headedness or unsteadiness2.2%102
30. Leukopenialow white blood cells2.2%99

Top 30 of 706 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 100 drugs in the kinase inhibitor class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 849,161 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 20.8% of reports give the United States as the country of the event or reporter.

Reason for use recorded

The indication field is filled in by the reporter and is often blank; shares are of all 4,544 reports.

Drugs most often listed in the same reports

Other products listed in reports where Lapatinib is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the kinase inhibitor class

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Lapatinib as a suspect or interacting product; reports listing it only as a concomitant medication (671) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.