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Ondansetron 4 mg/5mL Solution, 50 mL — NDC 00121-0882-51 package photo
Label image from the product's FDA listing (DailyMed) — may show a different pack size or an older label revision.

Ondansetron 4 mg/5mL Solution, 50 mL — NDC 0121-0882-51 (Billing 00121-0882-51)

by PAI Holdings, LLC dba PAI Pharma · 50 mL in 1 BOTTLE, PLASTIC

This is a package of 50 mL of Ondansetron 4 mg/5mL Solution from PAI Holdings, LLC dba PAI Pharma, marketed since Apr 2026 and currently FDA-listed; retail pharmacies pay about $0.2864 per mL (NADAC). It is this product's only package size.

NDC 00121-0882-51
🏷️ FDA NDC (as labeled) 0121-0882-51 billing pads the labeler segment with a zero
Rx only Generic On market Non-controlled ⇄ Compare with another NDC
🗂️ FDA directory synced Oct 1, 2026 · this listing last changed Jul 24, 2026 · sources: openFDA · FDA label (DailyMed) · FDA Orange & Purple Book · First Databank · CMS NADAC, ASP, Medicare & Medicaid · RxNorm
📋 All sources & update times →

This page is curated, coded, and maintained by

Compiled from public FDA, CMS, DailyMed, NADAC, and related drug data sources. Editorial policy

⚠️
Other active recalls for Ondansetron (different manufacturers) — 1 · tap to view
These affect other manufacturers’ products for the same ingredient — not necessarily the exact NDC on this page.
Class II · Dec 30, 2025 — 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. (Glenmark Pharmaceuticals Inc., USA) · FDA recall D-0246-2026
Each entry is an official FDA enforcement report — look up any recall number in the FDA recall database ↗

Identity & classification

Regulatory identifiers FDA, NLM and CMS codes for this package

FDA NDC (as labeled) 0121-0882-51
Product NDC 0121-0882
11-digit billing NDC 00121088251
NCPDP billing unit ML — per mL (volume)
RxCUI 312085
UNII NMH84OZK2B
UPC 0301210882517
Application # ANDA078127
SPL Set ID 68a4d845-0c1c-4867-bfca-c0fb11dc93cd
Established class (EPC) Serotonin-3 Receptor Antagonist
Mechanism of action Serotonin 3 Receptor Antagonists
DEA schedule Non-controlled
Marketing category ANDA
Marketing status On market
FDA listing status Listed (active directory)
Marketing start 2026-04-20
Route ORAL
Dosage form SOLUTION
Substance ONDANSETRON HYDROCHLORIDE
TE code (Orange Book) AA · RLD · RS

Drug-database identifiers Medi-Span GPI and First Databank GCN / HICL / AHFS classification

GPI-14 50250065052070
GCN Seq No 028107
GCN 20040
HICL code 006055
Ingredient (HICL) Ondansetron Hcl
HIC1 code H
Therapeutic class — broad (HIC1) Nervous System (Except Autonomic)
HIC2 code H6
Therapeutic class — intermediate (HIC2) Drugs Acting Principally On The Midbrain
HIC3 code H6J
Therapeutic class — specific (HIC3) Antiemetic/Antivertigo Agents
AHFS code 56:22.20.00
AHFS class 5-Ht3 Receptor Antagonists
FDB label name ONDANSETRON 4 MG/5 ML SOLUTION
FDB brand name Ondansetron Hcl
Legend status F — Federal legend — prescription drug or device
Quick answers
  • GSN (GCN sequence number): 028107
  • GCN: 20040
  • GPI-14 (Medi-Span): 50250065052070
  • HICL (First Databank): 006055
  • AHFS class code: 56:22.20.00
  • RxCUI (RxNorm): 312085
Why two NDCs? The FDA registers this code as 0121-0882-51 — a 4-4-2 layout, and that's what's printed on the package and shown on DailyMed. For insurance claims, every NDC is standardized to a uniform 11-digit 5-4-2 format by adding a zero to the labeler segment → 00121-0882-51. Same drug, same package — only the format differs.
Where does this data come from?
Identifiers from the FDA openFDA NDC Directory and Structured Product Labeling; RxCUI from RxNorm (NLM); GPI from Medi-Span; GCN / HIC / AHFS / legend from First Databank.

RxNorm drug class

This medicine 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
Where does this data come from?
Therapeutic classes from RxNorm RxClass (U.S. National Library of Medicine) — Established Pharmacologic Class (FDA), ATC drug family (WHO) and mechanism of action, matched by this product’s RxCUI.

Clinical

Label name ONDANSETRON 4 MG/5 ML SOLUTION Ingredient Ondansetron Hcl
📖 What it is MedlinePlus · NLM

Ondansetron is used to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, and surgery. Ondansetron is in a class of medications called serotonin 5-HT3 receptor antagonists. It works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.

Read the full MedlinePlus article ↗
📗 Our plain-language guide HelloPharmacist
  • 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 be...
  • What exactly is ondansetron used for — is it just for chemo patients?
  • 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 c...
  • How do I take the tablet or the dissolving tablet correctly?
📖 Read our full Ondansetron guide →
Where does this data come from?
Plain-language summary from MedlinePlus (U.S. National Library of Medicine); supplement & herbal interactions and nutrient depletion data from the Natural Medicines database; our full guide is HelloPharmacist editorial content.

Pricing

A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.

Price systemPer mLPer package
Retail pharmacies payNADAC · weekly $0.286 $14.32 / 50 ml
Medicaid paysCMS SDUD · 12 mo No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data.
Medicare drug plans payPart D · Q2 2026 $0.4859 $24.30 / 50 ml
Medicare Part B allowsASP · Q0162 $0.016 / Q0162 unit —
NADAC price history (per mL) — tap or hover for the price & month
Jun 2026 Jul 2026 Aug 2026 Sep 2026 $0.289 $0.280
▼ Down 1% over the last 4 months.
Where does this data come from?
NADAC (National Average Drug Acquisition Cost) is the CMS weekly pharmacy-acquisition-cost survey — what pharmacies pay. ASP (Average Sales Price) is the CMS Medicare Part B drug-payment file, published quarterly. Medicaid pays is computed by us from CMS State Drug Utilization Data (total reimbursed ÷ units, trailing 12 months) — gross of rebates and inclusive of dispensing fees, so it reflects what Medicaid paid, not an acquisition cost. Medicare drug plans pay is the median negotiated point-of-sale unit cost across plans listing this NDC in the CMS quarterly Prescription Drug Plan pricing files, before rebates. The VA pays is the federal contract price (FSS, and the statutory Big 4 ceiling where listed) from the VA National Acquisition Center pharmaceutical price file. All are free public government data; each measures a different payer, so the figures are not directly comparable.

Billing & reimbursement

FDA NDC (as labeled)0121-0882-51
11-digit billing NDC00121-0882-51
Format4-4-2 as registered → padded to 5-4-2 for billing (zero added to the labeler segment)
HCPCS J-codeQ0162
DescriptorONDANSETRON 1 MG, ORAL, FDA APPROVED PRESCRIPTION ANTI-EMETIC, FOR USE AS A COMPLETE THERAPEUTIC SUBSTITUTE FOR AN IV ANTI-EMETIC AT THE TIME OF CHEMOTHERAPY TREATMENT, NOT TO EXCEED A 48 HOUR DOSAGE REGIMEN
Billing units / pkg0.8 units
How the units are derivedThis package is 50 ML; the HCPCS unit is 1 MG, so one package = 0.8 billing units.
Medicare Part B spend (2026 (Q1))$34 · 127 claims · $0.27 per claim (all NDCs under Q0162)
Crosswalk sourcePDAC NDC-HCPCS crosswalk (DME MAC / DMEPOS)
Where does this data come from?
The HCPCS J-code crosswalk comes from the CMS ASP NDC-HCPCS crosswalk and the DMEPDAC (DME MAC) NDC-HCPCS crosswalk — free public CMS data. Billing units are derived from the code’s descriptor and the package amount.

Packaging — all sizes for this product

Package NDCDescription Marketing startMarketing endStatus
00121-0882-51 You're viewing this Main listing 50 mL in 1 BOTTLE, PLASTIC 2026-04-20 — Active

Therapeutic equivalents

ProductLabelerPackNADAC/unitTEStatusPrice vs. this
Ondansetron Hydrochloride 4 mg/5mL 00054-0064-47 Hikma 1 bottle $0.286 AA Availability likely —
Ondansetron 4 mg/5mLthis 00121-0882-51 PAI 50 ml $0.286 AA Availability likely —
Ondansetron 4 mg/5mL 16714-0671-02 NorthStar 1 bottle $0.286 AA Availability likely —
Ondansetron Hydrochloride 4 mg/5mL 62135-0555-58 Chartwell 50 ml $0.286 AA Availability likely —
Ondansetron 4 mg/5mL 65162-0691-79 Amneal 50 ml $0.286 AA Availability likely —
Ondansetron 4 mg/5mL 51672-4091-03 Taro 1 bottle $0.290 — Discontinued +1%
Ondansetron 4 mg/5mL 00121-4882-94 PAI 10 cups — AA FDA listed —
Ondansetron 4 mg/5mL 17856-0672-01 Atlantic 60 syringes — AA FDA listed —
Ondansetron 4 mg/5mL 17856-0691-01 ATLANTIC 1.5 ml — AA FDA listed —
Ondansetron 4 mg/5mL 50268-0647-14 AvPAK 40 cups — AA FDA listed —
Ondansetron 4 mg/5mL 60687-0252-86 American 10 cups — AA FDA listed —
Ondansetron 4 mg/5mL 65862-0208-04 Aurobindo 1 bottle — AA FDA listed —
Ondansetron 4 mg/5mL 68071-3611-05 NuCare 1 bottle — AA FDA listed —
Ondansetron Hydrochloride 4 mg/5mL 68094-0763-62 Precision 10 cups — AA FDA listed —
Ondansetron Hydrochloride 4 mg/5mL 68999-0555-24 Chartwell 10 cups — AA FDA listed —
About this product: this is a generic version of the medicine. FDA equivalence ratings are shown when available, and other versions are listed above, least expensive first.
Where does this data come from?
Equivalents are other NDCs of the same ingredient, form and route from the openFDA NDC Directory, ranked least-expensive-first by NADAC. Therapeutic-equivalence (AB) ratings come from the FDA Orange Book; biologics use the FDA Purple Book for biosimilar & interchangeable status.

Availability & generic status

🏛️
2026
On the market since
Apr 2026
📍
2026
Currently FDA-listed
listed with the FDA
🔓
·
Generic on the market
this product is a generic
✅This is a generic drug

This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.

Where does this data come from?
Patents and exclusivity from the FDA Orange Book (small-molecule drugs), refreshed from public FDA data. Generic launch timing is an estimate, not a guarantee.

What it looks like

Color yellow
FlavorStrawberry
One label can cover several strengths, so colors may be combined — always confirm a loose pill against the dispensed prescription label or a pharmacist.
Where does this data come from?
Physical description (imprint, shape, color, scoring, coating) from this product’s FDA Structured Product Labeling (SPL), mirrored from DailyMed / openFDA.

Inactive Ingredients / Excipients

Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.

💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.

  • UNII XF417D3PSL
    Anhydrous citric acid is a sour, crystalline powder derived from citric acid with water removed. In medicines, it acts as a buffer to control pH, adds tartness to improve taste, and helps tablets disintegrate.
  • UNII 6YSS42VSEV
    Fructose is a natural sugar derived from fruits and plants. It's used in medicines as a sweetener and filler to improve taste and add bulk to tablets or syrups.
  • UNII 8136Y38GY5
    A plant-derived thickening agent made from cellulose. It increases the thickness and consistency of liquid medicines, helping them coat surfaces and flow smoothly.
  • UNII OJ245FE5EU
    Sodium benzoate is a salt derived from benzoic acid, a preservative. It's added to medicines to prevent growth of bacteria, fungi, and other microorganisms that could spoil the product.
  • UNII B22547B95K
    A salt derived from citric acid that helps maintain the proper acid-base balance in the medicine. It's used as a buffer to keep the product stable and at the right pH level.
  • UNII 059QF0KO0R
    Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.

6 inactive ingredients listed in the exact product block matched to this NDC.

Where does this data come from?
Data sourced from official FDA Structured Product Labeling (SPL) via DailyMed — ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.

Inactive ingredient FAQ

Are inactive ingredients the same for every manufacturer?
No. Inactive ingredients can differ by manufacturer, dosage form, strength, and package / product version.
Why might an inactive ingredient be missing?
Some SPLs do not provide a complete structured inactive-ingredient list, and older or unusual labels may only include the information in narrative text.
Can inactive ingredients matter?
Yes. They can matter for allergies, intolerances, dyes, gluten / lactose concerns, preservatives, and formulation differences — but confirm with a pharmacist or the manufacturer when it’s clinically important.

Manufacturer & labeler

LabelerPAI Holdings, LLC dba PAI Pharma
Application holderPHARMACEUTICAL ASSOCIATES INC
FDA applicationANDA078127 (ANDA)
Labeler code00121
First marketedApr 2026
Product typeHuman Prescription Drug
Portfolio142 products on file
The labeler markets the product; the application holder owns the FDA approval. They’re often the same company but can differ (e.g. a repackager or an authorized generic). A mailing address / phone appears here when the manufacturer includes it in the product’s FDA label (not all do).
Where does this data come from?
Labeler, application holder and registered establishment from the FDA openFDA NDC Directory and Drugs@FDA; address/contact from the product’s FDA label.

Full prescribing information FDA SPL

The complete FDA label for this product — the official prescribing information, verbatim, section by section. Very long sections are excerpted here and marked; the full text is on DailyMed (linked in the sources below). Jump with a chip, search within the label, or expand everything.
🎯 Indications and Usage ⏱️ Dosage and Administration 💊 Dosage Forms and Strengths ⛔ Contraindications ⚠️ Warnings and Cautions 🤒 Adverse Reactions 🔄 Drug Interactions 👥 Use in Specific Populations 🤰 Pregnancy 🧒 Pediatric Use 🧓 Geriatric Use 🆘 Overdosage 🧬 Clinical Pharmacology 🧬 Mechanism of Action 📦 How Supplied / Storage and Handling 📋 Description 💬 Information for Patients 🧬 Pharmacokinetics 🧬 Pharmacodynamics 🔬 Clinical Studies 🔒 Drug Abuse and Dependence 🧪 Nonclinical Toxicology 📄 Carcinogenesis, Mutagenesis, Impairment of Fertility 📄 Package Label / Principal Display Panel
🎯 Indications and Usage 163 words ▾

1 INDICATIONS AND USAGE Ondansetron oral solution 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 oral solution is also indicated for the prevention of postoperative nausea and/or vomiting.

Ondansetron oral solution is a 5-HT3 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 )

⏱️ Dosage and Administration ~2 min read ▾

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 )

2.1Recommended Dosage The recommended dosage regimens for adult and pediatric patients are described in Table 1 and Table 2, respectively. Table 1: Adult Recommended Dosage Regimen for Prevention of Nausea and Vomiting Indication Dosage Regimen Highly Emetogenic Cancer Chemotherapy A single 24-mg dose administered 30 minutes before the start of single-day highly emetogenic chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 . Moderately Emetogenic Cancer Chemotherapy 8 mg administered 30 minutes before the start of chemotherapy, with a subsequent 8-mg dose 8 hours after the first dose.

Then administer 8 mg twice a day (every 12 hours) for 1 to 2 days after completion of chemotherapy. Radiotherapy For total body irradiation: 8 mg administered 1 to 2 hours before each fraction of radiotherapy each day. For single high-dose fraction radiotherapy to the abdomen: 8 mg administered 1 to 2 hours before radiotherapy, with subsequent 8-mg doses every 8 hours after the first dose for 1 to 2 days after completion of radiotherapy.

For daily fractionated radiotherapy to the abdomen: 8 mg administered 1 to 2 hours before radiotherapy, with subsequent 8-mg doses every 8 hours after the first dose for each day radiotherapy is given. Postoperative 16 mg administered 1 hour before induction of anesthesia. Table 2: Pediatric Recommended Dosage Regimen for Prevention of Nausea and Vomiting Indication Dosage Regimen Moderately Emetogenic Cancer Chemotherapy 12 to 17 years of age: 8 mg administered 30 minutes before the start of chemotherapy, with a subsequent 8-mg dose 8 hours after the first dose.

Then administer 8 mg twice a day (every 12 hours) for 1 to 2 days after completion of chemotherapy. 4 to 11 years of age: 4 mg administered 30 minutes before the start of chemotherapy, with a subsequent 4-mg dose 4 and 8 hours after the first dose. Then administer 4 mg three times a day for 1 to 2 days after completion of chemotherapy.

2.2Dosage in Hepatic Impairment In patients with severe hepatic impairment (Child-Pugh score of 10 or greater), do not exceed a total daily dose of 8 mg [see Use in Specific Populations ( 8.6 ), Clinical Pharmacology ( 12.3 )] .

💊 Dosage Forms and Strengths 59 words ▾

3 DOSAGE FORMS AND STRENGTHS Ondansetron oral solution, USP, a clear, colorless to light yellow liquid with strawberry flavor, contains 5 mg of ondansetron HCl dihydrate equivalent to 4 mg of ondansetron per 5 mL in white plastic bottles of 50 mL with child-resistant closures and 5 mL unit dose cups. Oral Solution: 4 mg/5 mL. ( 3 )

⛔ Contraindications 70 words ▾

4 CONTRAINDICATIONS Ondansetron oral solution 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 )

⚠️ Warnings and Cautions ~2 min read ▾

5 WARNINGS AND PRECAUTIONS Hypersensitivity Reactions, Including Anaphylaxis and Bronchospasm : Discontinue ondansetron oral solution 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 oral solution 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-HT3 receptor antagonists alone but particularly with concomitant use of serotonergic drugs. If such symptoms occur, discontinue ondansetron oral solution and initiate supportive treatment. If concomitant use of ondansetron oral solution 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 Distension Following Abdominal Surgery or Chemotherapy-Induced Nausea and Vomiting : Monitor for decreased bowel activity, particularly in patients with risk factors for gastrointestinal obstruction. ( 5.5 )

5.1Hypersensitivity Reactions Hypersensitivity reactions, including anaphylaxis and bronchospasm, have been reported in patients who have exhibited hypersensitivity to other selective 5-HT 3 receptor antagonists. If hypersensitivity reactions occur, discontinue use of ondansetron oral solution; treat promptly per standard of care and monitor until signs and symptoms resolve [see Contraindications ( 4 )].

5.2QT Prolongation Electrocardiogram (ECG) changes, including QT interval prolongation have been seen in patients receiving ondansetron. In addition, postmarketing cases of Torsade de Pointes have been reported in patients using ondansetron oral solution. Avoid ondansetron oral solution in patients with congenital long QT syndrome.

ECG monitoring is recommended in patients with electrolyte abnormalities (e.g., hypokalemia or hypomagnesemia), congestive heart failure, bradyarrhythmias, or patients taking other medicinal products that lead to QT prolongation [see Clinical Pharmacology ( 12.2 )].

5.3Serotonin Syndrome The development of serotonin syndrome has been reported with 5-HT 3 receptor antagonists alone. Most reports have been associated with concomitant use of serotonergic drugs (e.g., selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors, mirtazapine, fentanyl, lithium, tramadol, and intravenous methylene blue). Some of the reported cases were fatal.

Serotonin syndrome occurring with overdose of ondansetron alone has also been reported. The majority of reports of serotonin syndrome related to 5-HT 3 receptor antagonist use occurred in a post-anesthesia care unit or an infusion center. Symptoms associated with serotonin syndrome may include the following combination of signs and symptoms: mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, with or without gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).

Patients should be monitored for the emergence of serotonin syndrome, especially with concomitant use of ondansetron and other serotonergic drugs. If symptoms of serotonin syndrome occur, discontinue ondansetron and initiate supportive treatment. Patients should be informed of the increased risk of serotonin syndrome, especially if ondansetron is used concomitantly with other serotonergic drugs [see Drug Interactions ( 7.1 ), Overdosage ( 10 )] .

5.4Myocardial Ischemia Myocardial ischemia… [Excerpted — this section continues on DailyMed.]

🤒 Adverse Reactions ~3 min read ▾

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 ( 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 PAI Pharma at 1-800-845-8210 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1Clinical 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 trials of another drug and may not reflect the rates observed in practice. The following adverse reactions have been reported in clinical trials of patients treated with ondansetron, the active ingredient of ondansetron oral solution. A causal relationship to therapy with ondansetron was unclear in many cases.

Prevention of Chemotherapy- I nduced Nausea and Vomiting The most common adverse reactions reported in greater than or equal to 4% of 300 adults receiving a single 24-mg dose of ondansetron orally in 2 trials for the prevention of nausea and vomiting associated with highly emetogenic chemotherapy (cisplatin greater than or equal to 50 mg/m 2 ) were: headache (11%) and diarrhea (4%). The most common adverse reactions reported in 4 trials in adults for the prevention of nausea and vomiting associated with moderately emetogenic chemotherapy (primarily cyclophosphamide-based regimens) are shown in Table 3.

Table 3: Most Common Adverse Reactions in Adults Reported in greater than or equal to 5% of patients treated with ondansetron and at a rate that exceeded placebo. for the Prevention of Nausea and Vomiting Associated with Moderately Emetogenic Chemotherapy [Primarily Cyclophosphamide-based Regimens] Adverse Reaction Ondansetron 8 mg Twice Daily (n = 242) Placebo (n = 262) Headache 58 (24%) 34 (13%) Malaise/Fatigue 32 (13%) 6 (2%) Constipation 22 (9%) 1 (<1%) Diarrhea 15 (6%) 10 (4%) Less Common Adverse Reactions C entral Nervous System: Extrapyramidal reactions (less than 1% of patients).

H epatic: Aspartate transaminase (AST) and/or alanine transaminase (ALT) values exceeded twice the upper limit of normal in approximately 1% to 2% of 723 patients receiving ondansetron and cyclophosphamide-based chemotherapy in US clinical trials. The increases were transient and did not appear to be related to dose or duration of therapy. On repeat exposure, similar transient elevations in transaminase values occurred in some courses, but symptomatic hepatic disease did not occur.

The role of cancer chemotherapy in these biochemical changes is unclear. Liver failure and death has been reported in cancer patients receiving concurrent medications, including potentially hepatotoxic cytotoxic chemotherapy and antibiotics. The etiology of the liver failure is unclear.

Integumentary: Rash (approximately 1% of patients). Other (less than 2%): Anaphylaxis, bronchospasm, tachycardia, angina, hypokalemia, electrocardiographic alterations, vascular occlusive events, and grand mal seizures. Except for bronchospasm and anaphylaxis, the relationship to ondansetron is unclear.

Prevention of Radiation- I nduced Nausea and Vomiting The most common adverse reactions (greater than or equal to 2%) reported in patients receiving ondansetron and concurrent radiotherapy were similar to those reported in patients receiving ondansetr… [Excerpted — this section continues on DailyMed.]

🔄 Drug Interactions ~1 min read ▾

7 DRUG INTERACTIONS

7.1Serotonergic Drugs Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT 3 receptor antagonists and other serotonergic drugs, including SSRIs and SNRIs. Monitor for the emergence of serotonin syndrome. If symptoms occur, discontinue ondansetron oral solution and initiate supportive treatment [see Warnings and Precautions ( 5.3 )] .

7.2Drugs Affecting Cytochrome P-450 Enzymes Ondansetron does not itself appear to induce or inhibit the cytochrome P-450 drug-metabolizing enzyme system of the liver [see Clinical Pharmacology ( 12.3 )] . Because ondansetron is metabolized by hepatic cytochrome P-450 drug-metabolizing enzymes (CYP3A4, CYP2D6, CYP1A2), inducers or inhibitors of these enzymes may change the clearance and, hence, the half-life of ondansetron. In patients treated with potent inducers of CYP3A4 (i.e., phenytoin, carbamazepine, and rifampin), the clearance of ondansetron was significantly increased and ondansetron blood concentrations were decreased.

However, on the basis of available data, no dosage adjustment for ondansetron oral solution is recommended for patients on these drugs [see Clinical Pharmacology ( 12.3 )] .

7.3Tramadol Although no pharmacokinetic drug interaction between ondansetron and tramadol has been observed, data from 2 small trials indicate that when used together, ondansetron may increase patient-controlled administration of tramadol. Monitor patients to ensure adequate pain control when ondansetron is administered with tramadol.

7.4Chemotherapy Carmustine, etoposide, and cisplatin do not affect the pharmacokinetics of ondansetron. In a crossover trial in 76 pediatric patients, intravenous ondansetron did not increase systemic concentrations of high-dose methotrexate.

7.5Alfentanil and Atracurium Ondansetron does not alter the respiratory depressant effects produced by alfentanil or the degree of neuromuscular blockade produced by atracurium. Interactions with general or local anesthetics have not been studied.

👥 Use in Specific Populations ~3 min read ▾

8 USE IN SPECIFIC POPULATIONS

8.1Pregnancy Risk Summary Published epidemiological studies on the association between ondansetron use and major birth defects have reported inconsistent findings and have important methodological limitations that preclude conclusions about the safety of ondansetron use in pregnancy (see Data) . Available postmarketing data have not identified a drug-associated risk of miscarriage or adverse maternal outcomes. Reproductive studies in rats and rabbits did not show evidence of harm to the fetus when ondansetron was administered during organogenesis at approximately 6 and 24 times the maximum recommended human oral dose of 24 mg/day, based on body surface area (BSA), respectively ( see Data ) .

The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, miscarriages, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriages in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Data Human Data Available data on ondansetron use in pregnant women from several published epidemiological studies preclude an assessment of a drug-associated risk of adverse fetal outcomes due to important methodological limitations, including the uncertainty of whether women who filled a prescription actually took the medication, the concomitant use of other medications or treatments, recall bias, and other unadjusted confounders. Ondansetron exposure in utero has not been associated with overall major congenital malformations in aggregate analyses.

One large retrospective cohort study examined 1970 women who received a prescription for ondansetron during pregnancy and reported no association between ondansetron exposure and major congenital malformations, miscarriage, stillbirth, preterm delivery, infants of low birth weight, or infants small for gestational age. Two large retrospective cohort studies and one case-control study have assessed ondansetron exposure in the first trimester and risk of cardiovascular defects with inconsistent findings. Relative risks (RR) ranged from 0.97 (95% CI 0.86 to 1.10) to 1.62 (95% CI 1.04, 2.54).

A subset analysis in one of the cohort studies observed that ondansetron was specifically associated with cardiac septal defects (RR 2.05, 95% CI 1.19, 3.28); however, this association was not confirmed in other studies. Several studies have assessed ondansetron and the risk of oral clefts with inconsistent findings. A retrospective cohort study of 1.8 million pregnancies in the US Medicaid Database showed an increased risk of oral clefts among 88,467 pregnancies in which oral ondansetron was prescribed in the first trimester (RR 1.24, 95% CI 1.03, 1.48), but no such association was reported with intravenous ondansetron in 23,866 pregnancies (RR 0.95, 95% CI 0.63, 1.43).

In the subgroup of women who received both forms of administration, the RR was 1.07 (95% CI 0.59, 1.93). Two case-control studies, using data from birth defects surveillance programs, reported conflicting associations between maternal use of ondansetron and isolated cleft palate (OR 1.6 [95% CI 1.1, 2.3] and 0.5 [95% CI 0.3, 1.0]). It is unknown whether ondansetron exposure in utero in the cases of cleft palate occurred during the time of palate formation (the palate is formed between the 6th and 9th weeks of pregnancy).

Animal Data In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of ondansetron up to 15 mg/kg/day and 30 mg/kg/day, respectively, during the period of organogenesis. With the exception of a slight decrease in maternal body weight gain in the rabbits, there were no significant effects of ondansetron on the maternal animals or the development of the offspring. At doses of 15 mg/kg/day in rats and 30 mg/kg/day in rabbits, the maternal exposure margin was approximately 6 and 24 times the… [Excerpted — this section continues on DailyMed.]

🤰 Pregnancy ~3 min read ▾

8.1Pregnancy Risk Summary Published epidemiological studies on the association between ondansetron use and major birth defects have reported inconsistent findings and have important methodological limitations that preclude conclusions about the safety of ondansetron use in pregnancy (see Data) . Available postmarketing data have not identified a drug-associated risk of miscarriage or adverse maternal outcomes. Reproductive studies in rats and rabbits did not show evidence of harm to the fetus when ondansetron was administered during organogenesis at approximately 6 and 24 times the maximum recommended human oral dose of 24 mg/day, based on body surface area (BSA), respectively ( see Data ) .

The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, miscarriages, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriages in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Data Human Data Available data on ondansetron use in pregnant women from several published epidemiological studies preclude an assessment of a drug-associated risk of adverse fetal outcomes due to important methodological limitations, including the uncertainty of whether women who filled a prescription actually took the medication, the concomitant use of other medications or treatments, recall bias, and other unadjusted confounders. Ondansetron exposure in utero has not been associated with overall major congenital malformations in aggregate analyses.

One large retrospective cohort study examined 1970 women who received a prescription for ondansetron during pregnancy and reported no association between ondansetron exposure and major congenital malformations, miscarriage, stillbirth, preterm delivery, infants of low birth weight, or infants small for gestational age. Two large retrospective cohort studies and one case-control study have assessed ondansetron exposure in the first trimester and risk of cardiovascular defects with inconsistent findings. Relative risks (RR) ranged from 0.97 (95% CI 0.86 to 1.10) to 1.62 (95% CI 1.04, 2.54).

A subset analysis in one of the cohort studies observed that ondansetron was specifically associated with cardiac septal defects (RR 2.05, 95% CI 1.19, 3.28); however, this association was not confirmed in other studies. Several studies have assessed ondansetron and the risk of oral clefts with inconsistent findings. A retrospective cohort study of 1.8 million pregnancies in the US Medicaid Database showed an increased risk of oral clefts among 88,467 pregnancies in which oral ondansetron was prescribed in the first trimester (RR 1.24, 95% CI 1.03, 1.48), but no such association was reported with intravenous ondansetron in 23,866 pregnancies (RR 0.95, 95% CI 0.63, 1.43).

In the subgroup of women who received both forms of administration, the RR was 1.07 (95% CI 0.59, 1.93). Two case-control studies, using data from birth defects surveillance programs, reported conflicting associations between maternal use of ondansetron and isolated cleft palate (OR 1.6 [95% CI 1.1, 2.3] and 0.5 [95% CI 0.3, 1.0]). It is unknown whether ondansetron exposure in utero in the cases of cleft palate occurred during the time of palate formation (the palate is formed between the 6th and 9th weeks of pregnancy).

Animal Data In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of ondansetron up to 15 mg/kg/day and 30 mg/kg/day, respectively, during the period of organogenesis. With the exception of a slight decrease in maternal body weight gain in the rabbits, there were no significant effects of ondansetron on the maternal animals or the development of the offspring. At doses of 15 mg/kg/day in rats and 30 mg/kg/day in rabbits, the maternal exposure margin was approximately 6 and 24 times the maximum recommended human oral… [Excerpted — this section continues on DailyMed.]

🧒 Pediatric Use 155 words ▾

8.4Pediatric Use The safety and effectiveness of orally administered ondansetron have been established in pediatric patients 4 years and older for the prevention of nausea and vomiting associated with moderately emetogenic cancer chemotherapy. Use of ondansetron in these age-groups is supported by evidence from adequate and well-controlled studies of ondansetron in adults with additional data from 3 open-label, uncontrolled, non-US trials in 182 pediatric patients aged 4 to 18 years with cancer who were given a variety of cisplatin or noncisplatin regimens [see Dosage and Administration ( 2.2 ), Clinical Studies ( 14.1 )] .

Additional information on the use of ondansetron in pediatric patients may be found in ondansetron injection prescribing information. The safety and effectiveness of orally administered ondansetron have not been established in pediatric patients for: prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy. prevention of nausea and vomiting associated with radiotherapy. prevention of postoperative nausea and/or vomiting.

🧓 Geriatric Use 150 words ▾

8.5Geriatric Use Of the total number of subjects enrolled in cancer chemotherapy-induced and postoperative nausea and vomiting in US- and foreign-controlled clinical trials, for which there were subgroup analyses, 938 (19%) were aged 65 years and older. No overall differences in safety or effectiveness were observed between subjects 65 years of age and older and younger subjects. A reduction in clearance and increase in elimination half-life were seen in patients older than 75 years compared with younger subjects [see Clinical Pharmacology ( 12.3 )] .

There were an insufficient number of patients older than 75 years of age and older in the clinical trials to permit safety or efficacy conclusions in this age group. Other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. No dosage adjustment is needed in elderly patients.

🆘 Overdosage 172 words ▾

10 OVERDOSAGE There is no specific antidote for ondansetron overdose. Patients should be managed with appropriate supportive therapy. In addition to the adverse reactions listed above, the following adverse reactions have been described in the setting of ondansetron overdose: “Sudden blindness” (amaurosis) of 2 to 3 minutes’ duration plus severe constipation occurred in one patient that was administered 72 mg of ondansetron intravenously as a single dose.

Hypotension (and faintness) occurred in a patient that took 48 mg of ondansetron tablets. Following infusion of 32 mg over only a 4-minute period, a vasovagal episode with transient second-degree heart block was observed. In all instances, the adverse reactions resolved completely.

Pediatric cases consistent with serotonin syndrome have been reported after inadvertent oral overdoses of ondansetron (exceeding estimated ingestion of 5 mg per kg) in young children. Reported symptoms included somnolence, agitation, tachycardia, tachypnea, hypertension, flushing, mydriasis, diaphoresis, myoclonic movements, horizontal nystagmus, hyperreflexia, and seizure. Patients required supportive care, including intubation in some cases, with complete recovery without sequelae within 1 to 2 days.

🧬 Clinical Pharmacology ~3 min read ▾

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Ondansetron is a selective 5-HT 3 receptor antagonist. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. Serotonin receptors of the 5-HT 3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema.

It is not certain whether ondansetron’s antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. In humans, urinary 5-hydroxyindoleacetic acid (5-HIAA) excretion increases after cisplatin administration in parallel with the onset of emesis.

The released serotonin may stimulate the vagal afferents through the 5-HT 3 receptors and initiate the vomiting reflex.

12.2Pharmacodynamics In healthy subjects, single intravenous doses of 0.15 mg/kg of ondansetron had no effect on esophageal motility, gastric motility, lower esophageal sphincter pressure, or small intestinal transit time. Multiday administration of ondansetron has been shown to slow colonic transit in healthy subjects. Ondansetron has no effect on plasma-prolactin concentrations.

Cardiac Electrophysiology QTc interval prolongation was studied in a double-blind, single-intravenous dose, placebo- and positive-controlled, crossover trial in 58 healthy subjects. The maximum mean (95% upper confidence bound) difference in QTcF from placebo after baseline correction was 19.5 (21.8) milliseconds and 5.6 (7.4) milliseconds after 15­-minute intravenous infusions of 32 mg and 8 mg of ondansetron injection, respectively. A significant exposure-response relationship was identified between ondansetron concentration and ΔΔQTcF.

Using the established exposure-response relationship, 24 mg infused intravenously over 15 minutes had a mean predicted (95% upper prediction interval) ΔΔQTcF of 14.0 (16.3) milliseconds. In contrast, 16 mg infused intravenously over 15 minutes using the same model had a mean predicted (95% upper prediction interval) ΔΔQTcF of 9.1 (11.2) milliseconds. In this study, the 8-mg dose infused over 15 minutes did not prolong the QT interval to any clinically relevant extent.

12.3Pharmacokinetics Absorption Ondansetron is absorbed from the gastrointestinal tract and undergoes some first-pass metabolism. Mean bioavailability in healthy subjects, following administration of a single 8-mg tablet, is approximately 56%. Ondansetron systemic exposure does not increase proportionately to dose.

The area under curve (AUC) from a 16-mg tablet was 24% greater than predicted from an 8-mg tablet dose. This may reflect some reduction of first-pass metabolism at higher oral doses. Food Effects : Bioavailability is also slightly enhanced by the presence of food.

Distribution Plasma protein binding of ondansetron as measured in vitro was 70% to 76% over the concentration range of 10 to 500 ng/mL. Circulating drug also distributes into erythrocytes. Elimination Metabolism and Excretion: Ondansetron is extensively metabolized in humans, with approximately 5% of a radiolabeled dose recovered as the parent compound from the urine.

The metabolites are observed in the urine. The primary metabolic pathway is hydroxylation on the indole ring followed by subsequent glucuronide or sulfate conjugation. I n vitro metabolism studies have shown that ondansetron is a substrate for human hepatic cytochrome P-450 enzymes, including CYP1A2, CYP2D6, and CYP3A4.

In terms of overall ondansetron turnover, CYP3A4 played the predominant role. Because of the multiplicity of metabolic enzymes capable of metabolizing ondansetron, it is likely that inhibition or loss of one enzyme (e.g., CYP2D6 genetic deficiency) will be compensated by others and may result in little change in overall rates of ondansetron elimination. Although some nonconjugated metabolites have pharmacologic activi… [Excerpted — this section continues on DailyMed.]

🧬 Mechanism of Action 125 words ▾

12.1Mechanism of Action Ondansetron is a selective 5-HT 3 receptor antagonist. While its mechanism of action has not been fully characterized, ondansetron is not a dopamine-receptor antagonist. Serotonin receptors of the 5-HT 3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema.

It is not certain whether ondansetron’s antiemetic action is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. In humans, urinary 5-hydroxyindoleacetic acid (5-HIAA) excretion increases after cisplatin administration in parallel with the onset of emesis.

The released serotonin may stimulate the vagal afferents through the 5-HT 3 receptors and initiate the vomiting reflex.

📦 How Supplied / Storage and Handling 98 words ▾

16 HOW SUPPLIED/STORAGE AND HANDLING Ondansetron oral solution, USP, a clear colorless to light yellow liquid with strawberry flavor, contains 5 mg of ondansetron HCl dihydrate equivalent to 4 mg of ondansetron per 5 mL in: NDC 0121-0882-51: White plastic bottles of 50 mL with child resistant closures NDC 0121-4882-05: 5 mL unit dose cup NDC 0121-4882-94: Case contains 30 unit dose cups of 5 mL (0121-4882-05), packaged in 3 trays of 10 unit dose cups each Store at 20°C to 25°C (68°F to 77°F) [See USP Controlled Room Temperature].

Protect from light. Store bottles upright in cartons.

📋 Description 134 words ▾

11 DESCRIPTION The active ingredient in ondansetron oral solution, USP is ondansetron hydrochloride (HCl) as the dihydrate, the racemic form of ondansetron and a selective blocking agent of the serotonin 5-HT 3 receptor type. Chemically it is (±) 1, 2, 3, 9-tetrahydro-9-methyl-3-[(2-methyl-1H-imidazol-1-yl) methyl]-4H-carbazol-4-one, monohydrochloride, dihydrate. It has the following structural formula: The empirical formula is C 18 H 19 N 3 O•HCl•2H 2 O, representing a molecular weight of 365.9 g/mol.

Ondansetron hydrochloride dihydrate is a white to off-white powder that is soluble in water and normal saline. Each 5 mL of ondansetron oral solution, USP, contains 5 mg of ondansetron HCl dihydrate equivalent to 4 mg of ondansetron. Ondansetron oral solution, USP, contains the inactive ingredients anhydrous citric acid, fructose, hydroxyethyl cellulose, purified water, sodium benzoate, sodium citrate dihydrate, and strawberry flavor.

Onda-structure

💬 Information for Patients ~1 min read ▾

17 PATIENT COUNSELING INFORMATION Hypersensitivity Reactions Inform patients that ondansetron oral solution may cause hypersensitivity reactions, some as severe as anaphylaxis and bronchospasm. Instruct patients to immediately report any signs and symptoms of hypersensitivity reactions, including fever, chills, rash, or breathing problems to their healthcare provider [see Warnings and Precautions ( 5.1 )] . QT Prolongation Inform patients that ondansetron oral solution may cause serious cardiac arrhythmias, such as QT prolongation.

Instruct patients to tell their healthcare provider right away if they perceive a change in their heart rate, if they feel lightheaded, or if they have a syncopal episode [see Warnings and Precautions ( 5.2 )] . Drug Interactions Instruct the patient to report the use of all medications, especially apomorphine, to their healthcare provider. Concomitant use of apomorphine and ondansetron oral solution may cause a significant drop in blood pressure and loss of consciousness.

Advise patients of the possibility of serotonin syndrome with concomitant use of ondansetron oral solution and another serotonergic agent, such as medications to treat depression and migraines. Advise patients to seek immediate medical attention if the following symptoms occur: changes in mental status, autonomic instability, neuromuscular symptoms with or without gastrointestinal symptoms [see Warnings and Precautions ( 5.3 )] . Myocardial Ischemia Inform patients that ondansetron oral solution may cause myocardial ischemia.

Advise patients to seek immediate medical help if any symptoms suggestive of a myocardial ischemia occur, such as sudden chest pain or chest tightness [see Warnings and Precautions ( 5.4 )] . Masking of Progressive Ileus and Gastric Distension Inform patients following abdominal surgery or those with chemotherapy-induced nausea and vomiting that ondansetron oral solution may mask signs and symptoms of bowel obstruction. Instruct patients to immediately report any signs or symptoms consistent with a potential bowel obstruction to their healthcare provider [see Warnings and Precautions ( 5.5 )] .

Distributed by: PAI Pharma Greenville, SC 29605 www.paipharma.com R03/26

🧬 Pharmacokinetics ~3 min read ▾

12.3Pharmacokinetics Absorption Ondansetron is absorbed from the gastrointestinal tract and undergoes some first-pass metabolism. Mean bioavailability in healthy subjects, following administration of a single 8-mg tablet, is approximately 56%. Ondansetron systemic exposure does not increase proportionately to dose.

The area under curve (AUC) from a 16-mg tablet was 24% greater than predicted from an 8-mg tablet dose. This may reflect some reduction of first-pass metabolism at higher oral doses. Food Effects : Bioavailability is also slightly enhanced by the presence of food.

Distribution Plasma protein binding of ondansetron as measured in vitro was 70% to 76% over the concentration range of 10 to 500 ng/mL. Circulating drug also distributes into erythrocytes. Elimination Metabolism and Excretion: Ondansetron is extensively metabolized in humans, with approximately 5% of a radiolabeled dose recovered as the parent compound from the urine.

The metabolites are observed in the urine. The primary metabolic pathway is hydroxylation on the indole ring followed by subsequent glucuronide or sulfate conjugation. I n vitro metabolism studies have shown that ondansetron is a substrate for human hepatic cytochrome P-450 enzymes, including CYP1A2, CYP2D6, and CYP3A4.

In terms of overall ondansetron turnover, CYP3A4 played the predominant role. Because of the multiplicity of metabolic enzymes capable of metabolizing ondansetron, it is likely that inhibition or loss of one enzyme (e.g., CYP2D6 genetic deficiency) will be compensated by others and may result in little change in overall rates of ondansetron elimination. Although some nonconjugated metabolites have pharmacologic activity, these are not found in plasma at concentrations likely to significantly contribute to the biological activity of ondansetron.

Specific Populations Age: Geriatric Population: A reduction in clearance and increase in elimination half-life are seen in patients older than 75 years compared to younger subjects [see Use in Specific Populations ( 8.5 )] . Sex : Gender differences were shown in the disposition of ondansetron given as a single dose. The extent and rate of absorption are greater in women than men.

Slower clearance in women, a smaller apparent volume of distribution (adjusted for weight), and higher absolute bioavailability resulted in higher plasma ondansetron concentrations. These higher plasma concentrations may in part be explained by differences in body weight between men and women. It is not known whether these sex-related differences were clinically important.

More detailed pharmacokinetic information is contained in Tables 5 and 6. Table 5: Pharmacokinetics in Male and Female Healthy Subjects After a Single Dose of an Ondansetron 8-mg Tablet Age-group (years) Sex (M/F) Mean Weight (kg) N Peak Plasma Concentration (ng/mL) Time of Peak Plasma Concentration (h) Mean Elimination Half-life (h) Systemic Plasma Clearance L/h/kg Absolute Bioavailability 18-40 M F 69.0 62.7 6 5 26.2 42.7 2.0 1.7 3.1 3.5 0.403 0.354 0.483 0.663 61-74 M F 77.5 60.2 6 6 24.1 52.4 2.1 1.9 4.1 4.9 0.384 0.255 0.585 0.643 ≥75 M F 78.0 67.6 5 6 37.0 46.1 2.2 2.1 4.5 6.2 0.277 0.249 0.619 0.747 Table 6: Pharmacokinetics in Male and Female Healthy Subjects After a Single Dose of an Ondansetron 24­-mg Tablet Age-group (years) Sex (M/F) Mean Weight (kg) N Peak Plasma Concentration (ng/mL) Time of Peak Plasma Concentration (h) Mean Elimination Half-life (h) 18-43 M F 84.1 71.8 8 8 125.8 194.4 1.9 1.6 4.7

5.8Renal Impairment :Renal impairment is not expected to significantly influence the total clearance of ondansetron as renal clearance represents only 5% of the overall clearance. However, the mean plasma clearance of ondansetron was reduced by about 50% in patients with severe renal impairment (creatinine clearance less than 30 mL/min). The reduction in clearance was variable and not consistent with an increase in half-life [see Use in Specific Populations ( 8.7 )] .

Hepatic Impai… [Excerpted — this section continues on DailyMed.]

🧬 Pharmacodynamics 192 words ▾

12.2Pharmacodynamics In healthy subjects, single intravenous doses of 0.15 mg/kg of ondansetron had no effect on esophageal motility, gastric motility, lower esophageal sphincter pressure, or small intestinal transit time. Multiday administration of ondansetron has been shown to slow colonic transit in healthy subjects. Ondansetron has no effect on plasma-prolactin concentrations.

Cardiac Electrophysiology QTc interval prolongation was studied in a double-blind, single-intravenous dose, placebo- and positive-controlled, crossover trial in 58 healthy subjects. The maximum mean (95% upper confidence bound) difference in QTcF from placebo after baseline correction was 19.5 (21.8) milliseconds and 5.6 (7.4) milliseconds after 15­-minute intravenous infusions of 32 mg and 8 mg of ondansetron injection, respectively. A significant exposure-response relationship was identified between ondansetron concentration and ΔΔQTcF.

Using the established exposure-response relationship, 24 mg infused intravenously over 15 minutes had a mean predicted (95% upper prediction interval) ΔΔQTcF of 14.0 (16.3) milliseconds. In contrast, 16 mg infused intravenously over 15 minutes using the same model had a mean predicted (95% upper prediction interval) ΔΔQTcF of 9.1 (11.2) milliseconds. In this study, the 8-mg dose infused over 15 minutes did not prolong the QT interval to any clinically relevant extent.

🔬 Clinical Studies ~3 min read ▾

14 CLINICAL STUDIES

14.1Prevention of Chemotherapy-Induced Nausea and Vomiting Highly Emetogenic Chemotherapy In 2 randomized, double-blind, monotherapy trials, a single 24-mg oral dose of ondansetron was superior to a relevant historical placebo control in the prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 . Steroid administration was excluded from these clinical trials. More than 90% of patients receiving a cisplatin dose greater than or equal to 50 mg/m 2 in the historical-placebo comparator, experienced vomiting in the absence of antiemetic therapy.

The first trial compared oral doses of ondansetron 24 mg as a single dose, 8 mg every 8 hours for 2 doses, and 32 mg as a single dose in 357 adult cancer patients receiving chemotherapy regimens containing cisplatin greater than or equal to 50 mg/m 2 . The first or single dose was administered 30 minutes prior to chemotherapy. A total of 66% of patients in the ondansetron 24-mg once-a-day group, 55% in the ondansetron 8-mg twice-a-day group, and 55% in the ondansetron 32-mg once-a-day group, completed the 24-hour trial period with 0 emetic episodes and no rescue antiemetic medications, the primary endpoint of efficacy.

Each of the 3 treatment groups was shown to be statistically significantly superior to a historical placebo control. In the same trial, 56% of patients receiving a single 24-mg oral dose of ondansetron experienced no nausea during the 24-hour trial period, compared with 36% of patients in the oral ondansetron 8-mg twice-a-day group ( P = 0.001) and 50% in the oral ondansetron 32-mg once-a-day group. Dosage regimens of ondansetron 8 mg twice daily and 32 mg once daily are not recommended for the prevention of nausea and vomiting associated with highly emetogenic chemotherapy [see Dosage and Administration (2.1)] .

In a second trial, efficacy of a single 24-mg oral dose of ondansetron for the prevention of nausea and vomiting associated with highly emetogenic cancer chemotherapy, including cisplatin greater than or equal to 50 mg/m 2 , was confirmed. M oderately Emetogenic Chemotherapy A randomized, placebo-controlled, double-blind trial was conducted in the US in 67 patients receiving a cyclophosphamide-based chemotherapy regimen containing doxorubicin. The first 8-mg dose of ondansetron was administered 30 minutes before the start of chemotherapy, with a subsequent dose 8 hours after the first dose, followed by 8 mg of ondansetron twice a day for 2 days after the completion of chemotherapy.

Ondansetron was significantly more effective than placebo in preventing vomiting. Treatment response was based on the total number of emetic episodes over the 3-day trial period. The results of this trial are summarized in Table 7.

Table 7: Emetic Episodes - Treatment Response in Patients Receiving Moderately Emetogenic Chemotherapy (Cyclophosphamide-based Regimen Containing Doxorubicin) Ondansetron Tablets (n = 33) Placebo (n = 34) P- value Treatment response 0 Emetic episodes 1 to 2 Emetic episodes More than 2 emetic episodes/withdrawn 20 (61%) 6 (18%) 7 (21%) 2 (6%) 8 (24%) 24 (71%) < 0.001 < 0.001 Median number of emetic episodes

0.0Undefined Median undefined since at least 50% of the patients were withdrawn or had more than 2 emetic episodes. Median time to first emetic episode (hours) Undefined Median undefined since at least 50% of patients did not have any emetic episodes.

6.5In a double-blind, US trial in 336 patients receiving a cyclophosphamide-based chemotherapy regimen containing either methotrexate or doxorubicin, ondansetron 8 mg administered twice a day, was as effective as ondansetron 8 mg administered 3 times a day in preventing nausea and vomiting. Ondansetron 8 mg three times daily is not a recommended regimen for the treatment of moderately emetogenic chemotherapy [see Dosage and Administration ( 2.1 )] . Treatment response was based on the total number of e… [Excerpted — this section continues on DailyMed.]

🔒 Drug Abuse and Dependence 27 words ▾

9 DRUG ABUSE AND DEPENDENCE Animal studies have shown that ondansetron is not discriminated as a benzodiazepine nor does it substitute for benzodiazepines in direct addiction studies.

🧪 Nonclinical Toxicology 105 words ▾

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenic effects were not seen in 2-year studies in rats and mice with oral ondansetron doses up to 10 mg/kg per day and 30 mg/kg per day, respectively (approximately 4 and 6 times the maximum recommended human oral dose of 24 mg per day, based on BSA). Ondansetron was not mutagenic in standard tests for mutagenicity. Oral administration of ondansetron up to 15 mg/kg per day (approximately 6 times the maximum recommended human oral dose of 24 mg per day, based on BSA) did not affect fertility or general reproductive performance of male and female rats.

📄 Carcinogenesis, Mutagenesis, Impairment of Fertility 102 words ▾

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenic effects were not seen in 2-year studies in rats and mice with oral ondansetron doses up to 10 mg/kg per day and 30 mg/kg per day, respectively (approximately 4 and 6 times the maximum recommended human oral dose of 24 mg per day, based on BSA). Ondansetron was not mutagenic in standard tests for mutagenicity. Oral administration of ondansetron up to 15 mg/kg per day (approximately 6 times the maximum recommended human oral dose of 24 mg per day, based on BSA) did not affect fertility or general reproductive performance of male and female rats.

📄 Package Label / Principal Display Panel 72 words ▾

PACKAGE/LABEL PRINCIPAL DISPLAY PANEL - 50 mL Bottle 50 mL NDC 0121-0882-51 Ondansetron Oral Solution, USP 4 mg/5 mL Rx only PAI Pharma 50 mL - Bottle

PACKAGE/LABEL PRINCIPAL DISPLAY PANEL - 5 mL Unit Dose Cups Delivers 5 mL NDC 01221-4882-05 Ondansetron Oral Solution, USP 4 mg/5 mL Package Not Child-Resistant Rx only Dist.by: PAI Pharma Greenville, SC 29605 SEE INSERT Lidding Label - 5 mL Lidding Label - 5 mL

Source: FDA Structured Product Labeling, mirrored from DailyMed / openFDA. Prefer the government’s original formatting? View this label on DailyMed ↗

Medicare Part D spend CMS · PART D · 2026 (Q1)

Medicare Part D (outpatient prescription) spending for Ondansetron ODT (matched by generic name) — the program that covers self-administered drugs. 10 manufacturers.
⚠️ Drug-level data: CMS publishes Part D spending by drug, not by NDC — these figures combine every manufacturer, strength and package size sold under the name Ondansetron ODT. That’s a different level of aggregation than the Medicaid card above, which is specific to this exact 11-digit NDC (pack size included), so the two aren’t directly comparable.
Period
Total Part D spend
$27.68M
Claims incl. refills
1.5M
Beneficiaries
1.2M
Spend / beneficiary
$23.24
Spend / claim
$18.06
Trend by period
💵 About the dollar figures: spending is what Part D plans paid before confidential manufacturer rebates, so the program’s real net cost is lower. A blank patient count means fewer than 11 people — CMS hides counts that small to protect privacy. Source: CMS Medicare Quarterly Part D Spending by Drug (data.cms.gov), updated quarterly.
← 00121-0874-04 · PAI 00121-0885-08 · PAI →
For educational and professional reference only — not medical advice. Pricing reflects published NADAC and CMS ASP (free public data) and may differ from your acquisition cost; always verify before billing or dispensing.