This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.
Warnings the FDA chose to announce publicly after approval, as opposed to quiet label edits. Class-wide items name the drug's class, not this drug specifically.
Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.
Ondansetron is 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 is also indicated for the prevention of postoperative nausea and/or vomiting. Ondansetron is a 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 )
Ondansetron is contraindicated in patients: known to have hypersensitivity (e.g., anaphylaxis) to ondansetron or any of the components of the formulation [see Adverse Reactions (6.2) ]. receiving concomitant apomorphine due to the risk of profound hypotension and loss of consciousness. Patients known to have hypersensitivity (e.g. anaphylaxis) to ondansetron or any components of the formulation. ( 4 ) Concomitant use of apomorphine. ( 4 )
Hypersensitivity Reactions Including Anaphylaxis and Bronchospasm: Discontinue ondansetron if suspected. Monitor and treat promptly per standard of care until signs and symptoms resolve. ( 5.1 ) QT Interval Prolongation and Torsade de Pointes: Avoid ondansetron in patients with congenital long QT syndrome; monitor with electrocardiograms (ECGs) if concomitant electrolyte abnormalities, cardiac failure or arrhythmias, or use of other QT prolonging drugs. ( 5.2 ) Serotonin Syndrome: Reported with 5-HT 3 receptor antagonists alone but particularly with concomitant use of serotonergic drugs. If such symptoms occur, discontinue ondansetron and initiate supportive treatment. If concomitant use of ondansetron with other serotonergic drugs is clinically warranted, patients should be made aware of a potential increased risk for serotonin syndrome. ( 5.3 ) Myocardial Ischemia: Monitor or advise patients for signs and symptoms of myocardial ischemia after oral administration. ( 5.4 ) Masking of Progressive Ileus and/or Gastric Distention Following Abdominal Surgery or Chemotherapy-induced Nausea and Vomiting: Monitor for decreased bowel activity, particularly in patients with risk factors for...
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 (5.5) ] The most common adverse reactions in adults for the: prevention of chemotherapy-induced (greater than or equal to 5%) are: headache, malaise/fatigue, constipation, diarrhea. ( 6.1 ) prevention of radiation-induced nausea and vomiting (greater than or equal to 2%) are: headache, constipation, and diarrhea. ( 6.1 ) prevention of postoperative nausea and vomiting (greater than or equal to 9%) are: headache and hypoxia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Precision Dose, Inc. at 1-800-397-9228 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 cli...
Warnings and Precautions, Myocardial Ischemia ( 5.4 ) 10/2021
Source: FDA SPL label for Ondansetron Hydrochloride (Precision Dose Inc.), effective 20250530. Full label on DailyMed.
These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|
| 18,220 | 18,563 | 16,726 | 15,347 | 14,945 | 15,091 | 15,103 | 7,444 |
4,115 reports blaming this drug for every million Medicare prescriptions filled, which is 1.5× the typical drug on this site. (37,492 reports in 2024–2026, against 9,110,105 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)
Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.
| Date | Class | Firm | Reason |
|---|---|---|---|
| 12/2025 | Class II | Glenmark Pharmaceuticals Inc., USA | Defective container: Preferred Pharmaceuticals received a letter from the manufacturer Glenmark, that the blister packs are not fully sealed and tablets falling out. Preferred Pharmaceuticals purchased the finished product and repackaged th |
| 11/2023 | Class II | Baxter Healthcare Corporation | Failed pH Specifications |
| 04/2022 | Class II | Mckesson Medical-Surgical Inc. Corporate Office | cGMP deviations: Temperature abuse |
| 05/2019 | Class III | Fresenius Kabi USA, LLC | Failed Impurities/Degradation Specifications. |
| 09/2013 | Class II | Hospira Inc. | Presence of Particular Matter: Potential vendor glass issue - glass spiticules (glass strands) were identified during site inspection of the vials. |
| 05/2013 | Class II | Hospira, Inc. | Presence of Particulate; lot being recalled as a precaution due to the discovery of 2 particles found in a lot which preceded the recalled lot |
| 09/2012 | Class II | Fresenius Kabi USA, LLC | Lack of Assurance of Sterility: Glass vials may have finish fractures and glass particles. |
Class I = reasonable probability of serious harm. Class II = temporary or reversible harm. Class III = unlikely to harm. Most generic recalls are manufacturing or labeling defects for one lot, not a verdict on the molecule.
Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.
In 2024, drug companies reported $0 in payments to US physicians and hospitals tied to this drug across 0 transactions.
No pending federal MDL names this drug or its brands.
Not named in any federal pharmaceutical settlement of $100M or more on record.
Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.
| Product | Fills | $/fill |
|---|---|---|
| Ondansetron ODT | 4,929,800 | $15 |
| Ondansetron HCl | 4,180,305 | $16 |
Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.