Pharmacologic class (EPC) · 5 drug pages

Antihistamine: adverse event reports filed with FDA

15,698 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

15,698
reports across the class: 0.1% of all reports; 1,736
reports, 12 months to June 2026: 1,351 in the 12 months before; 74.8%
marked serious by the reporter: 57.4% across all reports; 5
drugs with a page: brand and generic names counted separately

Antihistamine is a pharmacologic class (an FDA Established Pharmacologic Class) with 5 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 15,698 adverse event reports received by FDA, 0.1% of the database, from January 2004 to June 2026.

1,736 reports arrived in the 12 months to June 2026, up 28% from 1,351 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 74.8% of the class's reports are marked serious, 35.2% record death among the outcomes and 29.1% record hospitalisation, as reported.

Across the class the reactions recorded most often are completed suicide (16.4%), toxicity to various agents (16%) and drug ineffective (12.5%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
Hydroxyzine	generic	8,643	907	92.5%	Completed suicide
Hydroxyzine hydrochloride	generic	2,500	417	83.4%	Toxicity to various agents
Doxylamine succinate	generic	1,858	252	43.3%	Drug ineffective
Unisom SleepTabsDoxylamine succinate	brand	1,559	87	7.6%	Drug ineffective
Hydroxyzine pamoate	generic	1,138	73	65.8%	Completed suicide

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

Completed suicidedeath by suicide16.4%2,572
Toxicity to various agentspoisoning or toxic effect of one or more substances16%2,517
Drug ineffectivethe medicine did not work as expected12.5%1,962
Drug abusemisuse of a medicine7.4%1,158
Somnolencedrowsiness6.3%982
Off label useused for a purpose or in a way not on the label4%635
Drug interactionan interaction between medicines4%634
Intentional overdosea deliberate overdose3.9%619
Overdosea dose above the recommended amount3.7%578
Cardiac arrestthe heart stopped3.7%577
Cardio-respiratory arrestthe heart and breathing stopped3.4%541
Deaththe patient died; cause not stated by this term3.3%511
Hypotensionlow blood pressure2.9%451
Pruritusitching2.7%427
Respiratory arrestbreathing stopped2.5%387
Coma2.3%367
Insomniadifficulty sleeping2.3%365
Suicide attempta suicide attempt2.3%356
Anxietyanxiety2.2%353
Fatiguetiredness2.1%331
Dizzinesslight-headedness or unsteadiness2%321
Condition aggravatedthe condition being treated got worse2%310
Nauseafeeling sick1.9%296
Electrocardiogram QT prolongeda QT prolongation on the ECG1.9%294
Falla fall1.8%286

Solid bar: share of all class reports. Hollow bar: the median share across the 5 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death35.2%5,524

Life-threatening6.7%1,057

Hospitalisation (initial or prolonged)29.1%4,563

Disability1.2%182

Congenital anomaly0.7%112

Other serious39.3%6,171

Not serious25.2%3,951

Patient age

Under 20.7%116

2 to 111.3%206

12 to 173.3%513

18 to 4428.1%4,416

45 to 6423.4%3,671

65 to 746.7%1,047

75 and over5.4%841

Age not given31.1%4,888

Who reported

Physician36.6%5,742

Pharmacist10%1,572

Other health professional24.4%3,828

Lawyer0.2%29

Consumer or non-health professional26.5%4,163

Not given2.3%364

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

Questions about Antihistamine reports

Which drugs are in the Antihistamine class on this site?

Hydroxyzine, Hydroxyzine hydrochloride, Doxylamine succinate, Unisom SleepTabs and Hydroxyzine pamoate. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

15,698 reports through June 2026, 1,736 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

completed suicide (16.4%), toxicity to various agents (16%), drug ineffective (12.5%), drug abuse (7.4%) and somnolence (6.3%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. 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 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.

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