What it's used for
Ondansetron tablets are used to prevent nausea and vomiting associated with cancer chemotherapy and radiation therapy, as well as to prevent postoperative nausea and vomiting.
Source: U.S. FDA-approved prescribing information (openFDA).
Typical dosing
Recommended dosage regimens for adult and pediatric patients are detailed in the prescribing information tables.
Dosing shown here is the general FDA-labeled range. Your prescribing clinician determines the exact dose, form, and schedule for you — this is not a substitute for medical advice.
Common side effects
Adverse reaction rates observed in clinical trials can vary and may not reflect rates observed in general clinical practice.
Covered strengths on the Tab $0 list
Covered at $0 with an active Tab membership when filled at a participating pharmacy nationwide or through mail order. A licensed clinician must prescribe the medication.
Related medications
Other everything else medications covered at $0 with an active Tab membership.
Ondansetron HCl cost without insurance
Cash prices for Ondansetron HCl without insurance vary widely by pharmacy, strength and quantity — the same prescription can cost very different amounts at two pharmacies in the same town. That is the problem a membership solves.
Ondansetron HCl is on Tab's covered $0 generic list. With an active Tab membership, every covered strength is $0 — not a percentage off, not a coupon that changes month to month — at participating pharmacies nationwide or through mail order. You do not need insurance, and Tab works whether or not you have a health plan.
Tab is a membership, not insurance. Covered medications require a prescription from a licensed clinician.
Ondansetron HCl dosage and administration
2. Dosage and Administration Section 2 DOSAGE AND ADMINISTRATION 2.1 Dosage The recommended dosage regimens for adult and pediatric patients are described in Table 1 and Table 2, respectively. Corresponding doses of ondansetron tablets, ondansetron orally disintegrating tablets and ondansetron oral solution may be used interchangeably. 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/m2 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.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Your prescribing clinician decides the exact dose, form and schedule for you — this is not medical advice.
Ondansetron HCl side effects
6. Adverse Reactions Section 6 ADVERSE REACTIONS 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical 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 tablets. A causal relationship to therapy with ondansetron was unclear in many cases.
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. This is not a complete list. Report side effects to your clinician, and seek care for anything severe or unexpected.
Ondansetron HCl drug interactions
7. Drug Interactions 7.1 Serotonergic Drugs Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT3 receptor antagonists and other serotonergic drugs, including SSRIs and SNRIs. Monitor for the emergence of serotonin syndrome. If symptoms occur, discontinue ondansetron and initiate supportive treatment [see WARNINGS AND PRECAUTIONS (5.3)]. 7.2 Drugs 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)].
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Tell your clinician and pharmacist about every medication, supplement and over-the-counter product you take.
Who should not take ondansetron hcl
4. Contraindications Ondansetron tablets are 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
Excerpt from the FDA-approved prescribing information (openFDA), retrieved 2026-09-15. Whether this medication is appropriate for you is a clinical decision made by your prescribing clinician.
Common questions
Is ondansetron HCl covered at $0 with Tab?
Yes. Ondansetron HCl is on Tab's covered $0 generic list — every covered strength is $0 with an active membership, at participating pharmacies nationwide or by mail order.
Do I need insurance to get ondansetron HCl through Tab?
No. Tab is a membership, not insurance. Covered medications are $0 with an active membership whether or not you have a health plan.
How do I get an ondansetron HCl prescription with Tab?
Book a video visit with a licensed Tab clinician (unlimited visits are included with membership). If it's clinically appropriate, they send the prescription to your chosen participating pharmacy or by mail order.
How much does ondansetron hcl cost without insurance?
Without insurance, retail cash prices for ondansetron hcl vary by pharmacy, strength and quantity. Ondansetron HCl is on Tab's covered $0 generic list, so every covered strength is $0 with an active Tab membership at participating pharmacies nationwide or by mail order.
What is the cheapest way to get ondansetron hcl?
For medications on Tab's covered list, a Tab membership is the cheapest route: covered strengths of ondansetron hcl are $0 with an active membership, and unlimited video visits with a licensed clinician are included, so the visit that produces the prescription is covered too.
What is the usual dose of ondansetron hcl?
2. Dosage and Administration Section 2 DOSAGE AND ADMINISTRATION 2.1 Dosage The recommended dosage regimens for adult and pediatric patients are described in Table 1 and Table 2, respectively. Corresponding doses of ondansetron tablets, ondansetron orally disintegrating tablets and ondansetron oral solution may be used interchangeably. (FDA-approved label, retrieved 2026-09-15. Your clinician sets your dose.)
What are the side effects of ondansetron hcl?
6. Adverse Reactions Section 6 ADVERSE REACTIONS 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice. (FDA-approved label, retrieved 2026-09-15.)
What interacts with ondansetron hcl?
7. Drug Interactions 7.1 Serotonergic Drugs Serotonin syndrome (including altered mental status, autonomic instability, and neuromuscular symptoms) has been described following the concomitant use of 5-HT3 receptor antagonists and other serotonergic drugs, including SSRIs and SNRIs. Monitor for the emergence of serotonin syndrome. (FDA-approved label, retrieved 2026-09-15. Tell your clinician about every medication and supplement you take.)
Ondansetron HCl is $0 on the covered list
Members pay $0 for covered generics at participating pharmacies nationwide or by mail order — plus unlimited virtual primary care, urgent care and dermatology visits. No insurance needed.
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