Trastuzumab: adverse event reports filed with FDA

28,929

reports as suspect product

0.1% of all reports · about 1,300 a year

2,893

reports, 12 months to June 2026

4,070 in the 12 months before

95.7%

marked serious by the reporter

86.6% across the class

11.9%

record death among outcomes, as reported

3,445 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 Trastuzumab reports recording the termmedian drug in her2/neu receptor antagonist

1. Diarrhoealoose or frequent stools11.7%3,392
2. Off label useused for a purpose or in a way not on the label9.9%2,862
3. Nauseafeeling sick8.3%2,412
4. Fatiguetiredness7.4%2,130
5. Myelosuppression5.9%1,696
6. Disease progressionthe disease advanced5.7%1,650
7. Vomitingbeing sick5.5%1,604
8. Neutropenialow neutrophils, a type of white blood cell5.1%1,485
9. Dyspnoeashortness of breath4.4%1,261
10. Pyrexiafever4.2%1,216
11. Anaemialow red blood cells4%1,158
12. Ejection fraction decreased3.9%1,132
13. Neuropathy peripheralnerve damage in hands or feet3.9%1,132
14. Astheniaweakness or lack of energy3.9%1,118
15. Deaththe patient died; cause not stated by this term3.5%1,008
16. Febrile neutropeniafever with low white blood cells3.4%979
17. Malignant neoplasm progression3.2%927
18. Cardiotoxicity3.1%901
19. Thrombocytopenialow platelets2.9%849
20. Decreased appetitereduced appetite2.8%807
21. Headachehead pain2.8%801
22. Metastases to central nervous system2.8%799
23. Rashskin rash2.7%778
24. Alopeciahair loss2.6%758
25. Pneumonialung infection2.5%715
26. Mucosal inflammation2.3%657
27. Coughcough2.2%642
28. Palmar-plantar erythrodysaesthesia syndrome2.1%617
29. Cardiac failureheart failure2.1%609
30. Constipationconstipation2.1%606

Top 30 of 2,212 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 6 drugs in the her2/neu receptor antagonist 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 85,553 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. 13% 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 28,929 reports.

Drugs most often listed in the same reports

Other products listed in reports where Trastuzumab 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 her2/neu receptor antagonist 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 Trastuzumab as a suspect or interacting product; reports listing it only as a concomitant medication (2,832) 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.