Reported Reactions

Drugs › Histamine-1 receptor antagonist

Generic name

Dimenhydrinate: adverse event reports filed with FDA

1,087 reports list it as a suspect or interacting product, 2004–2026. Class: Histamine-1 receptor antagonist. Also reported as Dimenhydrinate Injection.

1,087
reports as suspect product
0% of all reports · about 49 a year
121
reports, 12 months to June 2026
134 in the 12 months before
98.4%
marked serious by the reporter
57.7% across the class
13.8%
record death among outcomes, as reported
150 reports · not verified by FDA

1,087 adverse event reports received by FDA list dimenhydrinate, a generic name as a suspect or interacting product, from July 2004 to June 2026. A further 4,162 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, 121 reports listed it, down 10% from 134 in 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 49 reports a year and 0% of the 20,646,523 reports in the database, and 0.8% 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 drug ineffective (19.3%), nausea (13.7%) and off label use (13.2%). A report can list several reactions, so shares add to more than 100%; 482 different terms appear across these reports. Drug ineffective is recorded in 19.3% of these reports, about the same share as in the median histamine-1 receptor antagonist drug (15.9%).

98.4% of the reports are marked serious by the reporter (57.7% across the class); 13.8% record death among the outcomes and 47.5% record hospitalisation, as reported. 55.9% of the reports came from other health professionals, and the largest patient age group is 18 to 44 (19.7%). 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

01326Jul 2021: 13Aug 2021: 14Sep 2021: 17Oct 2021: 10Nov 2021: 7Dec 2021: 42022Jan 2022: 7Feb 2022: 8Mar 2022: 10Apr 2022: 11May 2022: 4Jun 2022: 3Jul 2022: 7Aug 2022: 5Sep 2022: 13Oct 2022: 8Nov 2022: 3Dec 2022: 82023Jan 2023: 9Feb 2023: 13Mar 2023: 20Apr 2023: 21May 2023: 8Jun 2023: 5Jul 2023: 6Aug 2023: 12Sep 2023: 18Oct 2023: 20Nov 2023: 17Dec 2023: 102024Jan 2024: 12Feb 2024: 7Mar 2024: 5Apr 2024: 26May 2024: 11Jun 2024: 4Jul 2024: 9Aug 2024: 16Sep 2024: 11Oct 2024: 7Nov 2024: 7Dec 2024: 152025Jan 2025: 11Feb 2025: 23Mar 2025: 5Apr 2025: 1May 2025: 15Jun 2025: 14Jul 2025: 10Aug 2025: 10Sep 2025: 17Oct 2025: 2Nov 2025: 5Dec 2025: 52026Jan 2026: 10Feb 2026: 13Mar 2026: 24Apr 2026: 6May 2026: 9Jun 2026: 10

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

0801592004: 420042005: 42006: 22007: 320072008: 22009: 112010: 1020102011: 202012: 102013: 1320132014: 342015: 132016: 1020162017: 152018: 332019: 7520192020: 1222021: 1402022: 8720222023: 1592024: 1302025: 11820252026: 72

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

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

  1. Drug ineffectivethe medicine did not work as expected19.3%210
  2. Nauseafeeling sick13.7%149
  3. Off label useused for a purpose or in a way not on the label13.2%144
  4. Falla fall12.6%137
  5. Pyrexiafever11.5%125
  6. Drug dependencedependence on a medicine10.9%119
  7. Respiratory depressionslow or shallow breathing10.6%115
  8. Vomitingbeing sick10.3%112
  9. Depressed moodlow mood9.8%107
  10. Insomniadifficulty sleeping9.2%100
  11. Dyspnoeashortness of breath9%98
  12. Malaisegeneral feeling of being unwell9%98
  13. Product use in unapproved indicationused for a purpose not on the label9%98
  14. Drug abusemisuse of a medicine8.7%95
  15. Chest discomfortchest discomfort8.6%93
  16. Fatiguetiredness8.6%93
  17. Foetal exposure during pregnancythe unborn baby was exposed to the medicine8.4%91
  18. Chest painchest pain8.3%90
  19. Febrile neutropeniafever with low white blood cells7.9%86
  20. Coughcough7.6%83
  21. Weight decreasedweight loss7.6%83
  22. Asthmaasthma7.5%82
  23. Nasopharyngitisa cold7.5%81
  24. Wheezingwheezing7.5%81
  25. Influenzaflu7.4%80
  26. Rhinorrhoeaa runny nose7.4%80

Top 30 of 482 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

Death13.8%150
Life-threatening10.5%114
Hospitalisation (initial or prolonged)47.5%516
Disability5.9%64
Congenital anomaly7%76
Other serious79.6%865
Not serious1.6%17

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 22.4%26
2 to 1112.8%139
12 to 174%44
18 to 4419.7%214
45 to 6418.5%201
65 to 7414.9%162
75 and over4.1%45
Age not given23.6%256

Patient sex

Female52.2%567
Male32%348
Not given15.8%172

Who reported

Physician24.2%263
Pharmacist3%33
Other health professional55.9%608
Lawyer0.1%1
Consumer or non-health professional14.5%158
Not given2.2%24

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 3.3% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Nausea968.8%
Constipation807.4%
Vomiting656%
Premedication615.6%
Morning sickness474.3%
Anxiety322.9%

The indication field is filled in by the reporter and is often blank; shares are of all 1,087 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Dimenhydrinate reports
Acetaminophen30027.6%
Pantoprazole27625.4%
Lorazepam20118.5%
Ondansetron18817.3%
Gabapentin18517%
Prednisone17716.3%
Furosemide16214.9%
Diphenhydramine14713.5%
Ergocalciferol14613.4%
Baclofen13512.4%

Other products listed in reports where Dimenhydrinate 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

MeasureDimenhydrinateHistamine-1 receptor antagonistAll reports
Reports as suspect product1,087135,66620,646,523
Share of that pool—0.8%0%
Reports, latest 12 months121—1,332,454
Marked serious98.4%57.7%57.4%
Death recorded among outcomes, per 1,000 reports13819091
Hospitalisation recorded, per 1,000 reports475203213
Consumer-filed share14.5%50.8%45.8%
Top term, share of reportsDrug ineffective 19.3%median 15.9%6.3%

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%
Benadrylbrand9,61243266.6%
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%

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 Dimenhydrinate reports

How many adverse event reports has FDA received for Dimenhydrinate?

1,087 reports list Dimenhydrinate as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 121 of them arrived in the latest 12 months. Another 4,162 list it only as a concomitant medication.

What reactions are recorded in Dimenhydrinate reports?

drug ineffective (19.3%), nausea (13.7%), off label use (13.2%), fall (12.6%) and pyrexia (11.5%). 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 Dimenhydrinate was responsible.

How serious are the reports?

98.4% are marked serious by the reporter. Among the outcomes recorded, 13.8% of reports include death and 47.5% 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?

other health professional (55.9%), physician (24.2%) and consumer or non-health professional (14.5%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Dimenhydrinate rising?

121 reports in the 12 months to June 2026, down 10% from 134 in 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 Dimenhydrinate 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 Dimenhydrinate?

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 Dimenhydrinate as a suspect or interacting product; reports listing it only as a concomitant medication (4,162) 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.