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Ondansetron

Ondansetron is an anti-nausea medication used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, and surgery.

Brand names ZofranZofran ODTZuplenzSumansetron
Drug classes Serotonin 3 Receptor Antagonists
Rx Forms 5
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026 Content updated Oct 2, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 211 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

✓No current FDA shortage listed · checked Oct 7, 2026 🚨Recall on record
Other forms & routes:
Injection
Ondansetron at a glance The quick version — the full detail is in the Patient Information Guide below.
Dr. Brian Staiger, PharmD, BCPS
The Pharmacist’s Take By · Clinical pharmacist · Written

Ondansetron (Zofran) is a go-to anti-nausea medicine for preventing nausea and vomiting from chemotherapy, radiation and surgery. It works by blocking serotonin's 5-HT3 receptors in the gut and the brain's vomiting center, and it has been around since about 1992 and is available as a generic. Most people tolerate it well, and headache and constipation are the usual complaints. The main thing to watch is heart rhythm, since it can prolong the QT interval (the heart's electrical recharge time), so report a fast, irregular or pounding heartbeat right away. Also tell prescribers if you take an antidepressant or tramadol, since the combination raises the risk of serotonin syndrome (agitation, fever, twitching).

Clinical pearls

  • Peel back the foil instead of pushing the dissolving tablet through, then let it melt on your tongue.
  • For chemotherapy or radiation, take it about 30 minutes beforehand, since it works best when started before nausea begins.
  • Never combine it with apomorphine, a Parkinson's medicine, because the pair can cause severe low blood pressure and fainting.
  • Report bloating or few bowel movements, especially after abdominal surgery, because ondansetron can hide a blocked bowel.
How we write & review this content — our editorial policy →
How you get itPrescription only
Comes asTablet, Orally disintegrating tablet, Injection +2
Earliest FDA record1991
Companies listing it with the FDA70
FDA label last updatedJan 11, 2023
FDA’s strongest warning (boxed)None on the label

Patient information guide A plain-language walkthrough of Ondansetron, written from its FDA label.

What Ondansetron is used for

▾

Ondansetron is approved to prevent nausea and vomiting in several specific clinical situations. The exact approvals depend on the form used:

  • Oral tablets, orally disintegrating tablets, and oral solution: prevent nausea and vomiting from highly emetogenic cancer chemotherapy (including high-dose cisplatin)
  • Oral tablets, orally disintegrating tablets, and oral solution: prevent nausea and vomiting from moderately emetogenic cancer chemotherapy
  • Oral tablets, orally disintegrating tablets, and oral solution: prevent nausea and vomiting in patients receiving radiation therapy — total body irradiation, single high-dose abdominal radiation, or daily abdominal fractions
  • Oral tablets, orally disintegrating tablets, and oral solution: prevent postoperative nausea and vomiting
  • Ondansetron injection (intravenous or intramuscular): prevents nausea and vomiting from emetogenic cancer chemotherapy, including high-dose cisplatin, in adults and children aged 6 months and older
  • Ondansetron injection: prevents postoperative nausea and vomiting in adults and children

How Ondansetron works

▾

Ondansetron is a selective 5-HT3 receptor antagonist — meaning it specifically blocks a type of serotonin receptor called the 5-HT3 receptor. When the body is exposed to chemotherapy, radiation, or the stress of surgery, cells in the small intestine release serotonin. That serotonin activates nearby nerve fibers and signals the brain's vomiting center (called the chemoreceptor trigger zone) to trigger nausea and vomiting. Ondansetron blocks those 5-HT3 receptors at both sites — in the gut and in the brain — interrupting the chain reaction before full-blown nausea sets in. It does not block dopamine receptors, which distinguishes it from some older anti-nausea drugs.

Ondansetron dosage

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Ondansetron comes in several forms — oral tablets, orally disintegrating tablets, oral solution, and injectable forms — each with specific timing instructions. Oral forms are generally taken about 30 minutes before chemotherapy or radiation begins, and additional doses may be taken later that day and for 1–2 days after chemotherapy, depending on the regimen. The injectable form is given by a healthcare professional before chemotherapy or surgery, following a specific schedule. Patients with severe liver disease have a lower maximum daily dose — your prescriber will set this for you. Always follow the exact schedule your prescriber provides, and do not skip or double doses without guidance.

Dosing details from the FDA-approved label

From the Ondansetron prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.

  • Prevention of nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy (adults and pediatric patients 6 months of age and older)
    • 0.15 mg/kg per dose for 3 doses, infused intravenously over 15 minutes
    • First dose 30 minutes before the start of chemotherapy and subsequent doses 4 and 8 hours after the first dose
    • Maximum: 16 mg per dose
    • Dilution in 50 mL of 5% Dextrose Injection or 0.9% Sodium Chloride Injection is required; pediatric patients 6 months to 1 year and/or 10 kg or less may be diluted in 10 to 50 mL
  • Prevention of postoperative nausea and/or vomiting (adults and pediatric patients older than 12 years of age)
    • 4 mg single dose, intravenously (undiluted, over at least 30 seconds and preferably longer, over 2 to 5 minutes) or intramuscularly (undiluted)
    • Administer immediately before induction of anesthesia, or postoperatively if no prophylactic antiemetic was given and nausea and/or vomiting occurs within 2 hours after surgery
    • Dilution not required; few patients above 80 kg have been studied
  • Prevention of postoperative nausea and/or vomiting (pediatric patients 1 month to 12 years and more than 40 kg)
    • 4 mg single dose, infused intravenously over at least 30 seconds and preferably longer (over 2 to 5 minutes)
    • Only studied in patients who had not received prophylactic ondansetron
  • Prevention of postoperative nausea and/or vomiting (pediatric patients 1 month to 12 years and 40 kg or less)
    • 0.1 mg/kg single dose, infused intravenously over at least 30 seconds and preferably longer (over 2 to 5 minutes)
    • Only studied in patients who had not received prophylactic ondansetron
  • Severe hepatic impairment (Child-Pugh score of 10 or greater)
    • A single maximal daily dose of 8 mg infused over 15 minutes beginning 30 minutes before the start of the emetogenic chemotherapy
    • Maximum: 8 mg total daily dose
    • No experience beyond first-day administration in these patients
Read the label’s full dosing text

DOSAGE AND ADMINISTRATION In controlled clinical trials, single doses of 25, 50, or 100 mg of sumatriptan tablets were effective for the acute treatment of migraine in adults. There is evidence that doses of 50 and 100 mg may provide a greater effect than 25 mg (see CLINICAL TRIALS ). There is also evidence that doses of 100 mg do not provide a greater effect than 50 mg. Individuals may vary in response to doses of sumatriptan tablets. The choice of dose should therefore be made on an individual basis, weighing the possible benefit of a higher dose with the potential for a greater risk of adverse events. If the headache returns or the patient has a partial response to the initial dose, the dose may be repeated after 2 hours, not to exceed a total daily dose of 200 mg. If a headache returns following an initial treatment with sumatriptan succinate injection, additional single sumatriptan tablets (up to 100 mg/day) may be given with an interval of at least 2 hours between tablet doses. The safety of treating an average of more than 4 headaches in a 30-day period has not been established. Because of the potential of MAO-A inhibitors to cause unpredictable elevations in the bioavailability of oral sumatriptan, their combined use is contraindicated (see CONTRAINDICATIONS ). Hepatic disease/functional impairment may also cause unpredictable elevations in the bioavailability of orally administered sumatriptan. Consequently, if treatment is deemed advisable in the presence of liver disease, the maximum single dose should in general not exceed 50 mg (see CLINICAL PHARMACOLOGY for the basis of this recommendation).

2 DOSAGE AND ADMINISTRATION • See full prescribing information for the recommended dosage in adults and pediatrics ( 2 ) • Patients with severe hepatic impairment: do not exceed a total daily dose of 8 mg ( 2.2 , 8.6 ) 2.1 Dosage The recommended dosage regimens for adult and pediatric patients are described in Table 1 and Table 2, respectively.

Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →

Ondansetron side effects

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Most people tolerate ondansetron well. Common side effects include:

Common side effects

  • Headache
  • Constipation
  • Diarrhea
  • Dizziness
  • Fatigue or tiredness
  • Flushing (warmth or redness in the face)

When to get medical help

  • Call your doctor right away if you notice a fast, irregular, or pounding heartbeat — ondansetron can affect your heart's electrical rhythm (QT prolongation)
  • Seek emergency help for signs of a severe allergic reaction: hives, swelling of the face or throat, trouble breathing, or loss of consciousness
  • Get help immediately for signs of serotonin syndrome: agitation, confusion, rapid heart rate, high fever, muscle twitching or stiffness, sweating
  • Tell your doctor if you have severe constipation, bloating, or reduced bowel movements — ondansetron can mask a serious bowel problem
  • Seek care promptly for chest pain or pressure, which may signal reduced blood flow to the heart (myocardial ischemia)

More serious reactions to watch for include an irregular or pounding heartbeat (a sign of QT prolongation), signs of a severe allergic reaction (hives, facial swelling, difficulty breathing), and signs of serotonin syndrome (confusion, agitation, rapid heart rate, high fever, muscle twitching). Seek medical help right away if any of these occur.

Ondansetron warnings and precautions

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  • QT prolongation and heart rhythm changes: Ondansetron can alter the heart's electrical rhythm in a dose-related way. In rare cases, this can cause a dangerous arrhythmia called Torsade de Pointes. People with congenital long QT syndrome should avoid the injectable form. ECG monitoring may be needed if you have heart failure, low potassium or magnesium, a slow heart rate, or take other QT-prolonging drugs.
  • Serotonin syndrome: Combining ondansetron with other serotonin-raising drugs can cause a rare but serious reaction with symptoms like agitation, rapid heart rate, high fever, and muscle twitching. Some reported cases have been fatal. Tell every provider about all your medications.
  • Myocardial ischemia (reduced blood flow to the heart): Cases have been reported, particularly with intravenous use. Do not exceed the recommended infusion rate. Report chest pain or pressure right away.
  • Masking bowel problems: After abdominal surgery or chemotherapy, ondansetron can hide signs of a slowing or blocked bowel. Your care team will monitor your bowel activity if this is a concern.
  • Hypersensitivity: Severe allergic reactions, including anaphylaxis and bronchospasm, have been reported, particularly in people who have reacted to similar anti-nausea drugs.

Ondansetron interactions

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Ondansetron can interact with several medications and substances — always share your full medication list with your prescriber and pharmacist:

  • Apomorphine — combining with ondansetron is contraindicated; it can cause profound low blood pressure and loss of consciousness
  • SSRIs and SNRIs (antidepressants like fluoxetine, sertraline, venlafaxine) — raise the risk of serotonin syndrome
  • MAO inhibitors (such as phenelzine or linezolid) — raise the risk of serotonin syndrome
  • Tramadol — ondansetron may reduce tramadol's effectiveness for pain relief; monitoring is needed
  • Fentanyl, lithium, mirtazapine, intravenous methylene blue — increased serotonin syndrome risk
  • Phenytoin, carbamazepine, rifampin — these drugs speed up ondansetron's breakdown, potentially making it less effective
  • Other QT-prolonging drugs — combining with ondansetron increases the risk of dangerous heart rhythm changes

Interactions listed in the FDA-approved label

From the Ondansetron prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.

  • Serotonergic drugs (including SSRIs and SNRIs): Serotonin syndrome (altered mental status, autonomic instability, neuromuscular symptoms) has been described with concomitant use of 5-HT3 receptor antagonists and other serotonergic drugs. Monitor for the emergence of serotonin syndrome; if symptoms occur, discontinue ondansetron and initiate supportive treatment.
  • Drugs affecting cytochrome P-450 enzymes (CYP3A4, CYP2D6, CYP1A2 inducers or inhibitors): Inducers or inhibitors of these enzymes may change the clearance and half-life of ondansetron; with potent CYP3A4 inducers (phenytoin, carbamazepine, rifampin) clearance was significantly increased and blood concentrations decreased. No dosage adjustment is recommended for patients on these drugs.
  • Tramadol: No pharmacokinetic interaction was observed, but data from 2 small trials indicate ondansetron may increase patient-controlled administration of tramadol. Monitor patients to ensure adequate pain control.
  • Chemotherapy (carmustine, etoposide, cisplatin): These do not affect the pharmacokinetics of ondansetron; intravenous ondansetron did not increase systemic concentrations of high-dose methotrexate in 76 pediatric patients.
  • Alfentanil and atracurium: Ondansetron does not alter the respiratory depressant effects of alfentanil or the degree of neuromuscular blockade produced by atracurium. Interactions with general or local anesthetics have not been studied.
Read the label’s full interactions text

Drug Interactions Monoamine Oxidase Inhibitors (MAO) Treatment with MAO-A inhibitors generally leads to an increase of sumatriptan plasma levels (see CONTRAINDICATIONS and PRECAUTIONS ). Due to gut and hepatic metabolic first-pass effects, the increase of systemic exposure after coadministration of an MAO-A inhibitor with oral sumatriptan is greater than after coadministration of the monoamine oxidase inhibitors (MAOI) with subcutaneous sumatriptan. In a study of 14 healthy females, pretreatment with an MAO-A inhibitor decreased the clearance of subcutaneous sumatriptan. Under the conditions of this experiment, the result was a 2-fold increase in the area under the sumatriptan plasma concentration x time curve (AUC), corresponding to a 40% increase in elimination half-life. This interaction was not evident with an MAO-B inhibitor. A small study evaluating the effect of pretreatment with an MAO-A inhibitor on the bioavailability from a 25 mg oral sumatriptan tablet resulted in an approximately 7-fold increase in systemic exposure. Alcohol Alcohol consumed 30 minutes prior to sumatriptan ingestion had no effect on the pharmacokinetics of sumatriptan.

Drug Interactions Selective Serotonin Reuptake Inhibitors/Serotonin Norepinephrine Reuptake Inhibitors and Serotonin Syndrome: Cases of life‑threatening serotonin syndrome have been reported during combined use of SSRIs or SNRIs and triptans (see WARNINGS ). Ergot-Containing Drugs Ergot-containing drugs have been reported to cause prolonged vasospastic reactions. Because there is a theoretical basis that these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and sumatriptan within 24 hours of each other should be avoided (see CONTRAINDICATIONS ). Monoamine Oxidase-A Inhibitors MAO-A inhibitors reduce sumatriptan clearance, significantly increasing systemic exposure.

Excerpted — the section continues on the label. Read the full Drug Interactions section on DailyMed →

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

🌿195 supplements and herbs with documented Ondansetron interactions, ranked by severity Check Ondansetron against a supplement or herb →

Before taking Ondansetron

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  • Do not take ondansetron if you have had a hypersensitivity (allergic) reaction to it or to other 5-HT3 receptor antagonists such as granisetron or dolasetron
  • Do not take ondansetron with apomorphine — this combination is contraindicated
  • Tell your doctor if you have congenital long QT syndrome, congestive heart failure, bradyarrhythmias (slow heart rhythm), or low potassium or magnesium levels
  • Tell your doctor if you have severe liver disease (hepatic impairment) — your daily dose must be limited
  • Tell your doctor if you are pregnant: studies have shown inconsistent findings about the risk of birth defects, including possible associations with oral clefts and cardiac septal defects with first-trimester use; discuss the risks and benefits with your provider
  • If you are breastfeeding, ondansetron passes into breast milk at low levels; available data suggest limited exposure to the infant, but discuss with your provider
  • Infants younger than 4 months clear ondansetron more slowly and require close monitoring
  • Adults older than 75 may also clear ondansetron more slowly; no routine dose change is required, but sensitivity may be greater
  • People with severe renal impairment (kidney disease) do not typically need a dose adjustment, but your provider should know

Ondansetron overdose

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There is no specific antidote for an ondansetron overdose. Supportive care is the main treatment. Reported effects of overdose include sudden brief vision loss, severe constipation, low blood pressure, and — particularly in young children who accidentally ingested large amounts — symptoms consistent with serotonin syndrome such as agitation, rapid heart rate, seizures, and muscle movements. If you suspect an overdose, seek emergency medical help immediately.

What Ondansetron does in the body

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At normal doses, ondansetron does not significantly affect esophageal or gastric movement, lower esophageal sphincter pressure, or small intestinal transit time. It does not affect heart rate, blood pressure, cardiac output, or stroke volume at single standard doses, and it has no effect on prolactin (a hormone) levels. However, it can slow movement through the colon with extended use, which explains why constipation is a common side effect. At higher intravenous doses, ondansetron prolongs the QT interval on an ECG in a dose-dependent manner — meaning the effect on heart rhythm grows with increasing dose.

How your body processes Ondansetron

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After an intravenous dose, ondansetron reaches peak blood levels quickly; after an intramuscular injection, peak levels are reached in about 40 minutes. The drug is 70–76% bound to proteins in the blood and also distributes into red blood cells. Ondansetron is broken down extensively by the liver using enzymes called CYP3A4, CYP1A2, and CYP2D6, with only about 5% leaving the body unchanged in the urine. In healthy adults, the elimination half-life (the time it takes for blood levels to fall by half) is roughly 3.5 hours, extending to about 5.5 hours in adults over 75. In young infants (under 4 months), the half-life is notably longer, meaning the drug stays in their system considerably longer than in older children or adults.

How to store Ondansetron

▾

Store at 20 to 25°C (68 – 77°F) . Dispense in a tight, light-resistant container as defined in the USP, with a child-resistant closure (as required).

Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

195

Supplements & herbs that interact with Ondansetron

195 supplements and herbal products have documented interactions with Ondansetron in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 4
  • Moderate · 145
  • Minor · 46
ACTIVATED CHARCOAL Major GRAPEFRUIT Major LITHIUM Major ST. JOHN'S WORT Major 1,3-DMAA Moderate 5-HTP Moderate ACACIA RIGIDULA Moderate ACETYL-L-CARNITINE Moderate +187 more
Every supplement checked against Ondansetron — ranked by severity The full interaction hub: 4 major · 145 moderate · 46 minor · every one linked to its full report. Check Ondansetron against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

Ondansetron: pharmacist answers to common questions

Quick, plain-English answers to the questions patients ask most about Ondansetron — the kind of thing our pharmacy team would talk through with you at the counter.

What exactly is ondansetron used for — is it just for chemo patients?

▾
Not at all. Ondansetron is approved to prevent nausea and vomiting from cancer chemotherapy, radiation therapy to the abdomen or whole body, and surgery. So you might receive it before a procedure in the hospital, during a course of radiation, or as part of cancer treatment. It's a preventive medication — it works best when taken before nausea starts, not after it's already hit.

How do I take the tablet or the dissolving tablet correctly?

▾
The regular tablet is swallowed like any other pill. The orally disintegrating tablet (ODT) is placed on your tongue and allowed to dissolve — don't chew or swallow it whole. For chemotherapy, you'll usually take it about 30 minutes before your treatment starts, and then possibly again hours later and for a day or two after. Your prescriber's exact schedule is what matters most, so follow that closely.

What side effects should I actually expect, and which ones mean I need to call someone?

▾
The most common side effects are headache and constipation — those are pretty typical with ondansetron. Some people also get dizziness, diarrhea, or flushing. The side effects worth calling about right away are an irregular or racing heartbeat, chest pain, any signs of a severe allergic reaction like hives or trouble breathing, or if you feel unusually agitated, confused, or have muscle twitching along with a fast heart rate — that combination can signal something called serotonin syndrome, which needs prompt attention.

Can I take ondansetron with my other medications?

▾
Some combinations are serious. You absolutely cannot take ondansetron with apomorphine — that combination can cause a dangerous drop in blood pressure. You also need to be careful with antidepressants like SSRIs or SNRIs, tramadol, certain antibiotics, and other drugs that affect heart rhythm. Tell your pharmacist and prescriber every medication you take, including any supplements, so they can check for interactions before you start.

I'm pregnant — is ondansetron safe for me to take?

▾
This is a really important question to ask your doctor directly. The research findings on ondansetron in pregnancy have been inconsistent — some studies suggest a possible small increase in the risk of oral clefts or certain heart defects in the first trimester, while others don't find that association. The picture isn't clear, and the FDA label doesn't give a simple yes or no. Your doctor will weigh the risk of untreated severe nausea against the potential concerns and help you decide what's best for you and your baby.

Does ondansetron affect my heart? I heard something about that.

▾
Yes, and it's worth knowing about. Ondansetron can slightly prolong something called the QT interval — a measure of your heart's electrical activity — and this effect gets bigger at higher doses. For most people this isn't a problem, but it can be more significant if you already have a heart condition, low potassium or magnesium levels, or if you take other medications that also affect heart rhythm. If any of those apply to you, your doctor may want to do a heart tracing (ECG) or monitor you more closely. If you ever feel a pounding, fluttering, or irregular heartbeat while on ondansetron, let your care team know right away.

Is Ondansetron available over the counter?

▾
No. Ondansetron is a prescription medicine: every Ondansetron product listed with the FDA is prescription only, so it is not sold over the counter. Your prescriber decides whether it is appropriate for you, and your pharmacist dispenses it.

When was Ondansetron first available?

▾
The earliest FDA record we hold for Ondansetron is from 1991: its first approval in Drugs@FDA or its earliest product listing in the NDC Directory, whichever is older. Many older medicines were in use before their first formal FDA approval, so this is the earliest date on record, not necessarily when Ondansetron was first used.

Who makes Ondansetron?

▾
70 companies currently list Ondansetron products in the FDA's NDC Directory, including NuCare Pharmaceuticals,Inc., Bryant Ranch Prepack, Proficient Rx LP. That count includes repackagers and distributors as well as manufacturers (companies that sell only the raw ingredient are not counted), so fewer companies actually make it; the label on your bottle names the one that supplied yours.

Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

More about Ondansetron on HelloPharmacist

📊Ondansetron supplement interactions195 checked — ranked by severity 🌿Drug & Supplement CheckerOndansetron vs. vitamins & herbs 💬Ask a PharmacistFree answer, usually < 24h 🔎NDC & pricing lookupFind Ondansetron NDCs & costs 🅰️Browse Drugs A–ZLook up any medication
Detailed data & references for Ondansetron Forms & strengths, pricing, billing codes, manufacturers, safety reports and sourcing — the data behind the page. Most people can stop here. Each section below opens on a tap.

Ondansetron forms and strengths (how it comes)

Ondansetron is available in 5 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Ondansetron inactive ingredients by manufacturer.

Tablet

By mouth
Brands Sumansetron
How this form is used
What it may be used for
  • Prevents nausea and vomiting from highly emetogenic cancer chemotherapy
  • Prevents nausea and vomiting from moderately emetogenic cancer chemotherapy
  • Prevents nausea and vomiting in patients receiving radiation therapy to the abdomen or whole body
  • Prevents postoperative nausea and vomiting
Important instructions
  • Take by mouth as directed, typically starting about 30 minutes before chemotherapy or radiation
  • For highly emetogenic chemotherapy, the dose is taken once before treatment; for moderately emetogenic chemotherapy, doses are taken before and then again hours later, and may continue for 1–2 days after chemotherapy
  • Patients with severe liver disease should not exceed the maximum daily dose their prescriber sets
  • Follow your prescriber's schedule exactly — do not adjust timing or doses on your own
Available strengths 4 strengths
4 mg 8 mg 16 mg 24 mg
229 FDA-listed product records ⓘ

Orally disintegrating tablet

By mouth
How this form is used
What it may be used for
  • Prevents nausea and vomiting from highly emetogenic cancer chemotherapy
  • Prevents nausea and vomiting from moderately emetogenic cancer chemotherapy
  • Prevents nausea and vomiting in patients receiving radiation therapy to the abdomen or whole body
  • Prevents postoperative nausea and vomiting
Important instructions
  • Place on the tongue and allow it to dissolve — do not chew or swallow whole
  • Take about 30 minutes before chemotherapy or radiation, as directed by your prescriber
  • Patients with severe liver disease should not exceed the maximum daily dose their prescriber sets
  • Follow your prescriber's full schedule, including any doses needed in the days after chemotherapy
Available strengths 5 strengths
4 mg 8 mg 16 mg 24 mg ONDANSETRON
216 FDA-listed product records ⓘ

Injection

Into a muscle · Into a vein
How this form is used
What it may be used for
  • Prevents nausea and vomiting from emetogenic cancer chemotherapy (including high-dose cisplatin) in adults and children 6 months and older
  • Prevents postoperative nausea and vomiting in adults and children
Important instructions
  • Given by a healthcare professional in a clinical setting — not self-administered at home
  • For chemotherapy, the injection is given intravenously, starting 30 minutes before the first chemotherapy dose, with additional doses given 4 and 8 hours later
  • For postoperative nausea and vomiting, the injection may be given intravenously or intramuscularly as directed by the clinical team
  • Do not exceed the recommended infusion rate — administering too quickly increases the risk of heart rhythm changes
Available strengths 2 strengths
2 mg/mL 4 mg/2 mL
107 FDA-listed product records ⓘ

Oral solution

By mouth
How this form is used
What it may be used for
  • Prevents nausea and vomiting from highly emetogenic cancer chemotherapy
  • Prevents nausea and vomiting from moderately emetogenic cancer chemotherapy
  • Prevents nausea and vomiting in patients receiving radiation therapy to the abdomen or whole body
  • Prevents postoperative nausea and vomiting
Important instructions
  • Take by mouth as a liquid, measured carefully with the provided measuring device
  • Take about 30 minutes before chemotherapy or radiation, following your prescriber's schedule
  • Patients with severe liver disease should not exceed the maximum daily dose their prescriber sets
  • Continue taking for the number of days after chemotherapy your prescriber specifies
Available strengths 1 strength
4 mg/5 mL
27 FDA-listed product records ⓘ

Dissolving oral film

By mouth
Available strengths 2 strengths
4 mg 8 mg
2 FDA-listed product records ⓘ

Ondansetron on the U.S. market: products, makers and brands

How Ondansetron appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

70 companies list 274 Ondansetron product records with the FDA, mostly as tablet, orally disintegrating tablet, injection; the earliest marketing or approval year on record is 1991. Brand names on the directory include Zofran, Zofran ODT, Zuplenz and 1 more; the rest are generics.

5
Dose forms ⓘ
70
Labelers (makers, repackagers, distributors)
4
Brand names
274
FDA-listed product records ⓘ
1991
Earliest FDA record ⓘ

FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

Also listed with the FDA, not a patient dose form: Powder (37) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.

NuCare Pharmaceuticals,Inc.8%
Bryant Ranch Prepack7%
Proficient Rx LP5%
A-S Medication Solutions4%
Cardinal Health 107, LLC3%
Preferred Pharmaceuticals, Inc.3%
Other makers69%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

How widely Ondansetron is used (Medicaid data)

A general measure of how commonly Ondansetron is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Ondansetron is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

10,434,600
Medicaid prescriptions filled (Q1–Q4 2025)
$163.8M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Ondansetron prescribed? Of the 1,601 medications we measure, Ondansetron ranks #9 by Medicaid prescriptions — more than 99% of them.

Where Ondansetron ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5
Total prescriptions — #9 of 1,601
#4 Atorvastatin 12,123,513 Rx #5 Cetirizine 12,078,490 Rx #6 Gabapentin 11,834,341 Rx #7 Amoxicillin 11,452,147 Rx #8 Fluticasone 11,068,970 Rx #9 Ondansetron 10,434,600 Rx #10 Fluticasone Nasal Spra... 9,154,113 Rx #11 Metformin 9,119,008 Rx #12 Hydroxyzine 9,012,994 Rx #13 Sertraline 8,868,838 Rx #14 Omeprazole 8,598,486 Rx

Utilization by Ondansetron product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

The 4 mg disintegrating oral tablet is the most-dispensed Ondansetron product — about 55% of these Medicaid prescriptions.

ondansetron 4 MG Disintegrating Oral Tablet Most dispensed

5,749,822 Medicaid prescriptions (Q1–Q4 2025) 55% of Ondansetron prescriptions shown $64.1M gross reimbursement (before rebates) ≈ $11 per prescription (gross)

Summed across the 12 of 214 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 104894

ondansetron 4 MG Oral Tablet

1,801,653 Medicaid prescriptions (Q1–Q4 2025) 17% of Ondansetron prescriptions shown $17.5M gross reimbursement (before rebates) ≈ $9.69 per prescription (gross)

Summed across the 15 of 233 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 198052

ondansetron 8 MG Disintegrating Oral Tablet

935,119 Medicaid prescriptions (Q1–Q4 2025) 9% of Ondansetron prescriptions shown $12.6M gross reimbursement (before rebates) ≈ $13 per prescription (gross)

Summed across the 14 of 195 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 312087

2 ML ondansetron 2 MG/ML Injection

828,480 Medicaid prescriptions (Q1–Q4 2025) 8% of Ondansetron prescriptions shown $45.4M gross reimbursement (before rebates) ≈ $55 per prescription (gross)

Summed across the 15 of 64 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1740467

ondansetron 0.8 MG/ML Oral Solution

592,968 Medicaid prescriptions (Q1–Q4 2025) 6% of Ondansetron prescriptions shown $11.6M gross reimbursement (before rebates) ≈ $20 per prescription (gross)

Summed across the 8 of 49 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 312085

ondansetron 8 MG Oral Tablet

452,840 Medicaid prescriptions (Q1–Q4 2025) 4% of Ondansetron prescriptions shown $5.3M gross reimbursement (before rebates) ≈ $12 per prescription (gross)

Summed across the 12 of 206 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 312086

ondansetron 2 MG/ML Injectable Solution

68,138 Medicaid prescriptions (Q1–Q4 2025) <1% of Ondansetron prescriptions shown $5.7M gross reimbursement (before rebates) ≈ $84 per prescription (gross)

Summed across the 11 of 32 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 283504

2 ML ondansetron 2 MG/ML Prefilled Syringe

4,443 Medicaid prescriptions (Q1–Q4 2025) <1% of Ondansetron prescriptions shown $640,399 gross reimbursement (before rebates) ≈ $144 per prescription (gross)

Summed across the 2 of 4 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1314133

ondansetron 16 MG Disintegrating Oral Tablet

1,137 Medicaid prescriptions (Q1–Q4 2025) <1% of Ondansetron prescriptions shown $1M gross reimbursement (before rebates) ≈ $902 per prescription (gross)

Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2685489

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Ondansetron, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 90 of 999 listed Ondansetron NDCs with Medicaid activity.

Compare Ondansetron products

A representative set of FDA-listed product records for Ondansetron — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Showing 200 of 274 products — FDA National Drug Code Directory. See every product, package size and price: browse all 274 Ondansetron NDCs →

Ondansetron recall history

A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.

The FDA’s enforcement reports list 3 Ondansetron recalls since July 2021. One of them is still ongoing and is listed first. A recall names specific lots from one company, so check the lot number on your own bottle rather than assuming every product is affected; your pharmacist can check whether your supply came from an affected lot.

Ongoing Class II Dec 30, 2025 · 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 the product for sale.
  • Ondansetron Orally Disintegrating Tablets, USP, 4mg, 30 Tablets (3 blistercards each containing 10 tablets), Rx only, Manufactured for: Glenmark Pharmaceuticals Inc., USA Mahwah, NJ 07430, Product of… Lots: Lot #: 19251311, Exp Date April 2027 FDA record D-0246-2026 →
Class II Nov 14, 2023 · Completed · Baxter Healthcare Corporation
Failed pH Specifications
  • Ondansetron Injection, USP, 4 mg/2 mL (2 mg/mL), 2 mL per vial, Rx only, Manufactured for: Baxter Healthcare Corporation, Deerfield, IL 60015 USA. Manufactured by: Baxter Pharmaceuticals India Privat… Lots: Lot # A0E0959A, A0E0961A, A0E1015A, A0E1020A, Exp. Date 30-Nov-23; A0F0016A, Exp. Date 31-Dec-23; A0F0260A, A0F0261A, A0F0262A, Exp. Date 29-Feb-24; A0F0414A, A0F0415A, A0F0416A, A0F0417A, A0F0418A, Exp. Date 30-Apr-24; A0F0503A, Exp. Date… FDA record D-0146-2024 →
Class II Apr 13, 2022 · Terminated · Mckesson Medical-Surgical Inc. Corporate Office
cGMP deviations: Temperature abuse
  • Ondansetron HCL, Tab 8 mg filmcoated, 30-count bottle, Rx only, MFG: Sandoz Pharma, NDC 65862-188-30 Lots: McKesson Medical-Surgical (MMS) is not able to identify the particular lot number received by a particular consignee for the recalled prescription products. Each letter includes the date it was distributed to customers and the dates that i… FDA record D-1103-2022 →

Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Ondansetron RxCUI 26225 8 dose forms · 15 strengths
  1. Dose form (SCDF) Disintegrating Oral Tablet RxCUI 373149 In current FDA listings
    Clinical drug / strength (SCD) 4 MG RxCUI 104894 8 MG RxCUI 312087 16 MG RxCUI 2685489 24 MG RxCUI 2685613
  2. Dose form (SCDF) Injectable Solution RxCUI 376327 In current FDA listings
    Clinical drug / strength (SCD) 2 MG/ML RxCUI 283504
  3. Dose form (SCDF) Injection RxCUI 1740463 In current FDA listings
    Clinical drug / strength (SCD) 2 ML ondansetron 2 MG/ML RxCUI 1740467
  4. Dose form (SCDF) Oral Film RxCUI 2269606 In current FDA listings
    Clinical drug / strength (SCD) 4 MG RxCUI 998033 8 MG RxCUI 998028
  5. Dose form (SCDF) Oral Solution RxCUI 373146 In current FDA listings
    Clinical drug / strength (SCD) 0.8 MG/ML RxCUI 312085
  6. Dose form (SCDF) Oral Tablet RxCUI 373148 In current FDA listings
    Clinical drug / strength (SCD) 4 MG RxCUI 198052 8 MG RxCUI 312086 16 MG RxCUI 692695 24 MG RxCUI 312084
  7. Dose form (SCDF) Prefilled Syringe RxCUI 1314132 No current FDA listing
    Clinical drug / strength (SCD) 2 ML ondansetron 2 MG/ML RxCUI 1314133
  8. Dose form (SCDF) Rectal Suppository RxCUI 373147 No current FDA listing
    Clinical drug / strength (SCD) 16 MG RxCUI 250587

Look up RxCUI 26225 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

💵 What Ondansetron costs pharmacies (NADAC benchmark)

The national average invoice price pharmacies pay for the drug itself, from CMS's NADAC survey (data as of Sep 30, 2026). This is a supply-cost benchmark — not a retail price and not what you'd pay at the counter.

FormStrengthPharmacy acquisition benchmark
Tablet, Orally Disintegrating · Oral 4 mg $0.120 per tablet NDC details & price history
Tablet, Orally Disintegrating · Oral 8 mg $0.169 per tablet NDC details & price history
Tablet, Film Coated · Oral 8 mg $0.078 per tablet NDC details & price history
Solution · Oral 4 mg/5 mL $0.286 per mL NDC details & price history
Why show this? Your out-of-pocket cost depends on insurance, pharmacy markup, and discounts — but the acquisition benchmark tells you whether the medication itself is inexpensive or costly, which strengths cost more per dose, and whether a cash-price quote is in a reasonable range. Each row links to the NDC-level record with its full price history.

Source: CMS National Average Drug Acquisition Cost (NADAC), a survey of retail pharmacy invoice prices. Benchmarks shown are the range across package sizes of a representative product for each form and strength — other manufacturers' products may differ.

Ondansetron brand names

Ondansetron is sold under 4 brand names in the FDA directory — Zofran, Zofran ODT, Zuplenz, Sumansetron. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.

Zofran Zofran ODT Zuplenz Sumansetron

Who makes Ondansetron: manufacturers and labelers

70 companies list Ondansetron products with the FDA. By number of product records, the largest are NuCare Pharmaceuticals,Inc., Bryant Ranch Prepack, Proficient Rx LP. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.

NuCare Pharmaceuticals,Inc. 22 Bryant Ranch Prepack 19 Proficient Rx LP 15 A-S Medication Solutions 12 Cardinal Health 107, LLC 9 Preferred Pharmaceuticals, Inc. 9 HF Acquisition Co LLC, DBA HealthFirst 8 Northwind Health Company, LLC 8 Remedyrepack Inc. 8 Chartwell RX, LLC 7 Advanced Rx of Tennessee, LLC 6 Asclemed USA, Inc. 6 Aurobindo Pharma Limited 6 PD-Rx Pharmaceuticals, Inc. 6 St. Mary's Medical Park Pharmacy 6 Sportpharm LLC 6 Sun Pharmaceutical Industries, Inc. 6 Fresenius Kabi USA, LLC 5 Hikma Pharmaceuticals USA Inc. 5 NorthStar Rx LLC 5 Dr. Reddy's Laboratories Limited 4 Glenmark Pharmaceuticals Inc., USA 4 Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc. 4 Hospira, Inc. 4

…and 46 more on the FDA NDC directory.

Ondansetron drug class (RxNorm)

Ondansetron belongs to the Serotonin-3 Receptor Antagonist class.

Pharmacologic class Serotonin-3 Receptor Antagonist
Drug family (ATC) Serotonin (5HT3) antagonists
How it works Serotonin 3 Receptor Antagonists

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

Sources for this Ondansetron page

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Jan 11, 2023
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Ondansetron.
📈
Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
🚨
Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Ondansetron after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
211
Finished products in the current FDA directory
274
Companies listing them (makers, repackagers, distributors)
70
FDA labeler codes behind them ⓘ
78
Linked representative label ⓘ
Actavis Pharma, Inc.
Linked label effective
Jan 11, 2023
Composite sections available
25
Linked SPL Set ID
b69f0762-a2f7-28c7-e053-2995a90a0484
Linked SPL Document ID
f2054b5e-a881-1bd5-e053-2a95a90a015c
Open the linked representative label on DailyMed ↗

How this page is built

HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Actavis Pharma, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →