Reported Reactions

Drugs › Histamine-1 receptor antagonist

Brand name · Diphenhydramine hydrochloride

Benadryl: adverse event reports filed with FDA

9,612 reports list it as a suspect or interacting product, 2004–2026. Class: Histamine-1 receptor antagonist. Also reported as Benadryl /00000402/, Benadryl Cream, Benadryl Injectable.

9,612
reports as suspect product
0.1% of all reports · about 427 a year
432
reports, 12 months to June 2026
458 in the 12 months before
66.6%
marked serious by the reporter
57.7% across the class
4.5%
record death among outcomes, as reported
436 reports · not verified by FDA

9,612 adverse event reports received by FDA list the brand name Benadryl (diphenhydramine hydrochloride) as a suspect or interacting product, from January 2004 to June 2026. A further 64,919 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 432 reports listed it, close to the 458 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 427 reports a year and 0.1% of the 20,646,523 reports in the database, and 7.1% of the reports for the histamine-1 receptor antagonist class. How many people take it is not in the data, so a count is not a rate of occurrence.

The MedDRA terms listed most often are somnolence (12.5%), fatigue (12.4%) and off label use (12.1%). A report can list several reactions, so shares add to more than 100%; 1,551 different terms appear across these reports. Somnolence is recorded in 12.5% of these reports, a larger share than in the median histamine-1 receptor antagonist drug (3.8%).

66.6% of the reports are marked serious by the reporter (57.7% across the class); 4.5% record death among the outcomes and 18.2% record hospitalisation, as reported. 59.9% of the reports came from consumers, and the largest patient age group is 45 to 64 (18%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

0141281Jul 2021: 30Aug 2021: 39Sep 2021: 64Oct 2021: 38Nov 2021: 51Dec 2021: 472022Jan 2022: 31Feb 2022: 46Mar 2022: 59Apr 2022: 57May 2022: 54Jun 2022: 60Jul 2022: 39Aug 2022: 146Sep 2022: 170Oct 2022: 281Nov 2022: 91Dec 2022: 792023Jan 2023: 61Feb 2023: 52Mar 2023: 46Apr 2023: 51May 2023: 63Jun 2023: 48Jul 2023: 25Aug 2023: 58Sep 2023: 45Oct 2023: 45Nov 2023: 41Dec 2023: 282024Jan 2024: 37Feb 2024: 36Mar 2024: 61Apr 2024: 63May 2024: 62Jun 2024: 54Jul 2024: 36Aug 2024: 57Sep 2024: 57Oct 2024: 46Nov 2024: 21Dec 2024: 292025Jan 2025: 32Feb 2025: 26Mar 2025: 34Apr 2025: 37May 2025: 40Jun 2025: 43Jul 2025: 47Aug 2025: 48Sep 2025: 38Oct 2025: 35Nov 2025: 31Dec 2025: 232026Jan 2026: 23Feb 2026: 34Mar 2026: 40Apr 2026: 36May 2026: 37Jun 2026: 40

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

05571,1132004: 12320042005: 2752006: 2402007: 18120072008: 1962009: 1572010: 33020102011: 1752012: 3092013: 32820132014: 3312015: 6332016: 61920162017: 4842018: 5252019: 56320192020: 6112021: 6532022: 1,11320222023: 5632024: 5592025: 43420252026: 210

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Benadryl reports recording the termmedian drug in histamine-1 receptor antagonist

  1. Somnolencedrowsiness12.5%1,204
  2. Fatiguetiredness12.4%1,194
  3. Off label useused for a purpose or in a way not on the label12.1%1,162
  4. Drug ineffectivethe medicine did not work as expected11.4%1,093
  5. Nauseafeeling sick9.6%923
  6. Drug hypersensitivityan allergic-type reaction to a medicine9.5%913
  7. Headachehead pain8%770
  8. Overdosea dose above the recommended amount7.6%731
  9. Pruritusitching7.6%726
  10. Infusion related reactiona reaction during or soon after an infusion7.1%683
  11. Dizzinesslight-headedness or unsteadiness7%674
  12. Urticariahives6.8%656
  13. Painpain, site not specified6.8%651
  14. Dyspnoeashortness of breath6.6%632
  15. Product use in unapproved indicationused for a purpose not on the label6.5%624
  16. Rashskin rash6.1%590
  17. Hypersensitivityan allergic-type reaction5.8%560
  18. Arthralgiajoint pain5.1%488
  19. Vomitingbeing sick4.9%467
  20. Malaisegeneral feeling of being unwell4.8%464
  21. Diarrhoealoose or frequent stools4.8%458
  22. Feeling abnormalfeeling odd or not right4.7%453
  23. Product use issuea problem in how the product was used4.7%450
  24. Insomniadifficulty sleeping4.3%415
  25. Astheniaweakness or lack of energy3.9%371
  26. Coughcough3.8%366
  27. Erythemaskin redness3.7%351
  28. Anxietyanxiety3.5%341
  29. Weight decreasedweight loss3.5%338

Top 30 of 1,551 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 34 drugs in the histamine-1 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

Death4.5%436
Life-threatening3%293
Hospitalisation (initial or prolonged)18.2%1,754
Disability1.7%162
Congenital anomaly0.3%31
Other serious54.3%5,221
Not serious33.4%3,208

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 135,666 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

Patient age

Under 21.1%109
2 to 112.5%237
12 to 172.9%276
18 to 4417.5%1,684
45 to 6418%1,726
65 to 746.6%632
75 and over4.2%406
Age not given47.3%4,542

Patient sex

Female57.3%5,512
Male22%2,117
Not given20.6%1,983

Who reported

Physician11.8%1,139
Pharmacist1.9%182
Other health professional21.1%2,024
Lawyer0.4%37
Consumer or non-health professional59.9%5,753
Not given5%477

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 81.1% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Premedication1,11011.5%
Hypersensitivity4875.1%
Pruritus2802.9%
Urticaria1962%
Rash1461.5%
Multiple allergies971%

The indication field is filled in by the reporter and is often blank; shares are of all 9,612 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Benadryl reports
Tylenol1,15512%
Prednisone9119.5%
Acetaminophen8408.7%
Remicade6787.1%
Zyrtec5315.5%
Rituximab4104.3%
Diphenhydramine hydrochloride3904.1%
Methotrexate3763.9%
Aspirin3733.9%
Ibuprofen3613.8%

Other products listed in reports where Benadryl 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

MeasureBenadrylHistamine-1 receptor antagonistAll reports
Reports as suspect product9,612135,66620,646,523
Share of that pool—7.1%0.1%
Reports, latest 12 months432—1,332,454
Marked serious66.6%57.7%57.4%
Death recorded among outcomes, per 1,000 reports4519091
Hospitalisation recorded, per 1,000 reports182203213
Consumer-filed share59.9%50.8%45.8%
Top term, share of reportsSomnolence 12.5%median 3.8%1%

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 histamine-1 receptor antagonist class

DrugName typeReportsLatest 12 monthsMarked serious
Zyrtecbrand20,34292916.7%
Cetirizine hydrochloridegeneric19,0922,04377.5%
Diphenhydraminegeneric15,3391,15796%
Cetirizinegeneric12,5221,54891.7%
Allegra Allergybrand7,8683043.6%
Diphenhydramine hydrochloridegeneric5,55653894.6%
Xyzal Allergy 24HRbrand5,3021473.3%
Cetirizine hydrochloride, pseudoephedrine hydrochloridegeneric4,91490999.3%
Xyzalbrand3,82418144.6%
Fexofenadinegeneric3,14233562.5%
Diphenhydramine hclgeneric2,741091%
Desloratadinegeneric2,69919093.6%
Azelastine hydrochloridegeneric2,5021515.7%
Aleve PMbrand1,877136.4%
Azelastinegeneric1,5484011.6%

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.

Questions about Benadryl reports

How many adverse event reports has FDA received for Benadryl?

9,612 reports list Benadryl as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 432 of them arrived in the latest 12 months. Another 64,919 list it only as a concomitant medication.

What reactions are recorded in Benadryl reports?

somnolence (12.5%), fatigue (12.4%), off label use (12.1%), drug ineffective (11.4%) and nausea (9.6%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Benadryl was responsible.

How serious are the reports?

66.6% are marked serious by the reporter. Among the outcomes recorded, 4.5% of reports include death and 18.2% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

consumer or non-health professional (59.9%), other health professional (21.1%) and physician (11.8%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Benadryl rising?

432 reports in the 12 months to June 2026, close to the 458 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Benadryl was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Benadryl?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

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 Benadryl as a suspect or interacting product; reports listing it only as a concomitant medication (64,919) 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.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.