Pharmacologic class (EPC) · 4 drug pages

Serotonin-3 receptor antagonist: adverse event reports filed with FDA

22,267 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.

22,267
reports across the class: 0.1% of all reports; 1,867
reports, 12 months to June 2026: 2,192 in the 12 months before; 86.9%
marked serious by the reporter: 57.4% across all reports; 4
drugs with a page: brand and generic names counted separately

Serotonin-3 receptor antagonist is a pharmacologic class (an FDA Established Pharmacologic Class) with 4 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 22,267 adverse event reports received by FDA, 0.1% of the database, from February 2004 to June 2026.

1,867 reports arrived in the 12 months to June 2026, down 15% from 2,192 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 86.9% of the class's reports are marked serious, 13.8% record death among the outcomes and 37.5% record hospitalisation, as reported.

Across the class the reactions recorded most often are nausea (12.6%), off label use (9.9%) and drug ineffective (9.3%). 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
Ondansetron	generic	17,524	1,561	91.4%	Nausea
Ondansetron hydrochloride	generic	2,330	255	93.1%	Off label use
Granisetron	generic	1,246	51	61.4%	Nausea
SancusoGranisetron	brand	1,167	0	33.5%	Product adhesion issue

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

Nauseafeeling sick12.6%2,798
Off label useused for a purpose or in a way not on the label9.9%2,199
Drug ineffectivethe medicine did not work as expected9.3%2,067
Vomitingbeing sick8%1,785
Pyrexiafever6.5%1,452
Painpain, site not specified6.1%1,362
Constipationconstipation5.9%1,319
Product use in unapproved indicationused for a purpose not on the label5.8%1,299
Fatiguetiredness5.4%1,212
Headachehead pain5.3%1,179
Hyperhidrosisexcessive sweating5.2%1,147
Electrocardiogram QT prolongeda QT prolongation on the ECG4.8%1,068
Dyspnoeashortness of breath4.5%1,013
Maternal exposure during pregnancythe mother took the medicine during pregnancy4.5%1,011
Drug interactionan interaction between medicines4.5%1,010
Rashskin rash4.2%942
Exposure during pregnancythe medicine was taken during pregnancy4.2%941
Hypertensionhigh blood pressure4.1%919
Serotonin syndrometoo much serotonin activity, with agitation, fever and tremor4.1%919
Diarrhoealoose or frequent stools4.1%907
Foetal exposure during pregnancythe unborn baby was exposed to the medicine4%893
Anxietyanxiety3.7%831
Abdominal painstomach or belly pain3.7%813
Hypersensitivityan allergic-type reaction3.5%787
Deaththe patient died; cause not stated by this term3.3%745

Solid bar: share of all class reports. Hollow bar: the median share across the 4 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death13.8%3,073

Life-threatening13.5%3,016

Hospitalisation (initial or prolonged)37.5%8,359

Disability3.6%793

Congenital anomaly3.5%788

Other serious59.2%13,181

Not serious13.1%2,922

Patient age

Under 21.4%318

2 to 112.9%638

12 to 173.6%793

18 to 4419%4,227

45 to 6423.4%5,206

65 to 7412%2,672

75 and over7.9%1,753

Age not given29.9%6,660

Who reported

Physician28.3%6,291

Pharmacist10.9%2,436

Other health professional42.3%9,413

Lawyer0.7%154

Consumer or non-health professional15.2%3,392

Not given2.6%581

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 Serotonin-3 receptor antagonist reports

Which drugs are in the Serotonin-3 receptor antagonist class on this site?

Ondansetron, Ondansetron hydrochloride, Granisetron and Sancuso. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

22,267 reports through June 2026, 1,867 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?

nausea (12.6%), off label use (9.9%), drug ineffective (9.3%), vomiting (8%) and pyrexia (6.5%).

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.