Histamine-1 receptor antagonist: adverse event reports filed with FDA

135,666

reports across the class

0.7% of all reports

10,050

reports, 12 months to June 2026

12,083 in the 12 months before

57.7%

marked serious by the reporter

57.4% across all reports

34

drugs with a page

brand and generic names counted separately

Drugs in the 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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

1. Drug ineffectivethe medicine did not work as expected23%31,212
2. Fatiguetiredness13.8%18,701
3. Off label useused for a purpose or in a way not on the label12.4%16,869
4. Painpain, site not specified12.3%16,739
5. Rheumatoid arthritisrheumatoid arthritis, an inflammatory joint disease10.7%14,488
6. Rashskin rash10.1%13,733
7. Abdominal discomfortstomach discomfort9.9%13,368
8. Alopeciahair loss9.5%12,931
9. Systemic lupus erythematosuslupus, an autoimmune disease9.5%12,889
10. Hypersensitivityan allergic-type reaction9.3%12,673
11. Pemphigus9.3%12,561
12. Infusion related reactiona reaction during or soon after an infusion9.2%12,497
13. Glossodynia8.8%11,919
14. Headachehead pain8.6%11,631
15. Swellingswelling8.3%11,307
16. Product use issuea problem in how the product was used8.3%11,222
17. Hand deformity8%10,858
18. Joint swellinga swollen joint7.8%10,644
19. Hepatic enzyme increasedraised liver enzymes7.8%10,566
20. Pruritusitching7.8%10,557
21. Wound7.8%10,522
22. Contraindicated product administered7.6%10,360
23. Arthropathy7.6%10,334
24. Drug intolerancethe medicine was not tolerated7.6%10,285
25. Maternal exposure during pregnancythe mother took the medicine during pregnancy7.5%10,185

Solid bar: share of all class reports. Hollow bar: the median share across the 34 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

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 class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.