Ondansetron: Side Effects, Uses & Monitoring
Prevention of nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including high-dose cisplatin.
- Data source
- FDA labeling via NIH DailyMed (label a360d43c…)
- Label version
- current
- Last reviewed
- 2026
Reported adverse reactions
Reactions listed in current FDA labeling, with the highest frequency reported across summarized placebo-controlled trials.
| Adverse reaction (as reported in labeling) | Reported frequency* |
|---|---|
| Diarrhea | 44% |
| Pyrexia | 41% |
| Headache | 25% |
| Fever | 8% |
| Akalhisia | 6% |
| Reactions* | 5% |
| Paresthesia | 2% |
*Highest percentage reported for the active moiety across placebo-controlled trial tables in current FDA labeling. Values reflect trial reporting, not your individual risk.
Labeled uses (from FDA prescribing information)
Prevention of nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including high-dose cisplatin. Efficacy of the 32 mg single dose beyond 24 hours in these patients has not been established. Prevention of postoperative nausea and/or vomiting. As with other antiemetics, routine prophylaxis is not recommended for patients in whom there is little expectation that nausea and/or vomiting will occur postoperatively. In patients where nausea and/or vomiting must be avoided postoperatively, ondansetron injection, USP is recommended even where the incidence of postoperative nausea and/or vomiting is low. For patients who do not receive prophylactic ondansetron injection, USP and experience nausea and/or vomiting postoperatively, ondansetron injection, USP may be given to prevent further episodes (see CLINICAL TRIALS ).
Frequently Asked Questions
What is Ondansetron used for?
FDA labeling lists the approved uses shown above under "Labeled uses." This summary is informational; only a qualified prescriber can determine whether a medication is appropriate for you.
What are the most commonly reported side effects of Ondansetron?
The table above shows adverse reactions and the highest frequencies reported in placebo-controlled trials summarized in current FDA labeling for Ondansetron. Individual risk varies.
Does Ondansetron require lab monitoring?
Monitoring needs vary. Ask your healthcare provider whether any lab tests apply while taking Ondansetron.
Where does this information come from?
All clinical facts on this page were extracted from the current FDA-registered product labeling for this ingredient, published by manufacturers through NIH DailyMed. See the source link below.
Medical disclaimer: Educational content extracted from public FDA labeling. Not medical advice. Always consult a qualified healthcare professional before starting, stopping, or changing any medication.