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This page presents data from the FDA Adverse Event Reporting System (FAERS) and the FDA-approved drug label. A report submitted to FAERS does not prove a drug caused the reported event. Always consult a healthcare provider about medications.

Ondansetron Hydrochloride (ondansetron)

Last updated: June 20, 2026
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Ondansetron Hydrochloride is the brand name for ondansetron. According to the FDA-approved label, Ondansetron tablets are indicated for the prevention of nausea and vomiting associated with: highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 . initial and repeat courses of moderately emetogenic cancer chemotherapy. FAERS contains 105,948 submissions naming this drug from 2003 through 2026; the top three reactions cited are nausea, fatigue, and diarrhoea.

Most-Reported Reactions

Counts of the reactions most often cited in FAERS submissions that named Ondansetron Hydrochloride. Inclusion here does not establish causation - submitters describe what was observed, not what was confirmed. One submission can list several reactions, so the totals exceed the report count.

NAUSEA 11,916 (11.2%) FATIGUE 8,587 (8.1%) DIARRHOEA 8,066 (7.6%) VOMITING 7,521 (7.1%) OFF LABEL USE 6,673 (6.3%) DEATH 4,995 (4.7%) PYREXIA 4,890 (4.6%) DYSPNOEA 4,867 (4.6%) FEBRILE NEUTROPENIA 4,592 (4.3%) PAIN 4,499 (4.2%) HEADACHE 4,341 (4.1%) CONSTIPATION 4,005 (3.8%) ASTHENIA 3,788 (3.6%) DRUG INEFFECTIVE 3,712 (3.5%) PNEUMONIA 3,518 (3.3%)

Patient Demographics

Patient sex and age across the FAERS submissions that named Ondansetron Hydrochloride. Percentages here are computed only from submissions where these fields were filled in - many leave them blank.

By Sex

Female Male Unknown

By Age Group

0-17 18-44 45-64 65+

Severity Outcomes

Severity flags recorded across the 105,948 FAERS submissions that named Ondansetron Hydrochloride. Each bar shows the count of those reports carrying that flag. A single case can carry more than one (a hospitalization that became life-threatening, for example), so these bars are independent rates - they don't sum to 100%. Inclusion of a case under any flag does not establish that the drug caused the outcome.

DEATH 13,696 (12.9%) HOSPITALIZATION 48,032 (45.3%) LIFE-THREATENING 8,718 (8.2%) DISABLING 2,516 (2.4%)

Submissions Per Quarter

Quarterly count of FAERS submissions that named Ondansetron Hydrochloride. Ups and downs on this chart can track prescribing volume, news cycles, or shifts in how reports get filed, rather than the drug becoming safer or more dangerous.

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026

From the FDA-Approved Label

Excerpts from the official FDA-approved prescribing information for Ondansetron Hydrochloride. This is the authoritative source on indications, warnings, and known adverse reactions.

Indications

1 INDICATIONS AND USAGE Ondansetron tablets are indicated for the prevention of nausea and vomiting associated with: highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 . initial and repeat courses of moderately emetogenic cancer chemotherapy. radiotherapy in patients receiving either total body irradiation, single high-dose fraction to the abdomen, or daily fractions to the abdomen Ondansetron tablets are also indicated for the prevention of postoperative nausea and/or vomiting. Ondansetron tablets are 5-HT 3 receptor antagonist indicated for the prevention of: nausea and vomiting associated with highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 (1) nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy (1) nausea and vomiting associated with radiotherapy in patients receiving either total body irradiation, single high-dose fraction to the abdomen, or daily fractions to the abdomen (1) postoperative nausea and/or vomiting (1)

Adverse Reactions (from label)

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Hypersensitivity Reactions [see Warnings and Precautions ( 5.1 )] QT Prolongation [see Warnings and Precautions (5.2 )] Serotonin Syndrome [see Warnings and Precautions ( 5.3 )] Myocardial Ischemia [see Warnings and Precautions ( 5.4 )] Masking of Progressive Ileus and Gastric Distension [see Warnings and Precautions [see Warnings and Precautions ( 5.5 )] The most common adverse reactions in adults for the: prevention of chemotherapy-induced (≥5%) are: headache, malaise/fatigue, constipation, diarrhea ( 6.1 ) prevention of radiation-induced nausea and vomiting (≥2%) are: headache, constipation, and diarrhea ( 6.1 ) prevention of postoperative nausea and vomiting (≥9%) are: headache and hypoxia ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Dr. Reddy's Laboratories Inc., at 1-888-375-3784 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical tria...

FDA label effective date: 2024-04-24

Disclaimer

AdverseEvent.ai is not affiliated with the FDA. Adverse-event counts come from the FDA Adverse Event Reporting System (FAERS). Drug labels come from the FDA drug label dataset. A report submitted to FAERS does not prove a drug caused the reported event — always consult a healthcare provider about medications. This site is for informational purposes only and is not medical advice.