Ondansetron: Uses, Dose, Side Effects and Brands in India (2026)

• Updated 9 October 2026
• Reviewed by Sudhanshu Singhal
• 20 min read
• 30 sources

Every MRP above comes from the Tata 1mg listing read on 9 October 2026, and MRPs change from batch to batch and over time, so the price at a chemist may differ.

What is ondansetron?

Ondansetron is a selective 5-HT3 receptor antagonist, which in plain words means it blocks one particular type of serotonin receptor. The US FDA Zofran label states that it is not a dopamine-receptor antagonist, and the UK SmPC gives it the ATC code A04AA01 (serotonin 5HT3 antagonist).

How it works

Chemotherapy appears to make the lining of the small intestine release serotonin, and the released serotonin can stimulate the vagus nerve through 5-HT3 receptors and start the vomiting reflex. The FDA label explains that ondansetron blocks that receptor, and it adds that the site of the action — central, peripheral or both — is not certain; the UK SmPC likewise says the precise mode of action in controlling nausea and vomiting is not known. MedlinePlus, the US National Library of Medicine patient information, describes it simply as a medicine that works by blocking the action of serotonin, a natural substance that may cause nausea and vomiting.

The FDA label also states that ondansetron does not stimulate movement of the stomach or intestine, so it must not be used in place of nasogastric suction. Strength is expressed as ondansetron base: each 5 mL of the US oral solution holds 5 mg ondansetron hydrochloride dihydrate, equal to 4 mg ondansetron.

Forms and strengths sold in India

The forms listed in India's NLEM 2022 are tablet 4 mg, tablet 8 mg, oral liquid 2 mg/5 mL and injection 2 mg/mL. One important point for patients and pharmacists: the Indian oral liquid strength of 2 mg/5 mL is half the US and WHO oral solution strength of 4 mg/5 mL, so millilitre figures from a foreign label must never be copied across to an Indian bottle. The US Zofran label lists tablets 4 mg and 8 mg, orally disintegrating tablets 4 mg and 8 mg, oral solution 4 mg/5 mL and a separate injection label of 2 mg/mL.

For mouth-dissolving tablets (ODT), the FDA label says to peel back the foil rather than push the tablet through, use dry hands, and place the tablet on top of the tongue, where it dissolves in seconds and is swallowed with saliva without liquid. The UK orodispersible SmPC gives the same handling, and notes that the 4 mg ODT contains 3 mg aspartame, a phenylalanine source, so care is needed in phenylketonuria.

On absorption, the FDA label gives mean oral bioavailability of about 56% after one 8 mg tablet, with food slightly increasing bioavailability. Time to peak blood level after an 8 mg tablet was 1.7 to 2.2 hours in healthy adults, and the elimination half-life was 3.1 to 6.2 hours depending on age and sex. The UK SmPC reports a peak of about 30 ng/mL in about 1.5 hours after an 8 mg oral dose, and a terminal half-life of about 3 hours. Ondansetron is broken down mainly by the liver enzyme CYP3A4, with CYP2D6 and CYP1A2 also taking part.

Combination partners

The products described on this page, including the Vibcare range, are single-ingredient ondansetron products, and the labels read do not describe a fixed-dose combination. The one co-administration the UK SmPC states is that a single oral dose of up to 24 mg for highly emetogenic chemotherapy may be given with 12 mg oral dexamethasone sodium phosphate, which is a separate medicine prescribed alongside by the treating doctor.

What is ondansetron used for?

As the labels state, ondansetron is used to prevent nausea and vomiting caused by chemotherapy and radiotherapy and to prevent nausea and vomiting after an operation. Nothing in this section is a recommendation to use the medicine for any other purpose, and every use below must be decided by a doctor.

The US Zofran tablets/ODT/oral solution label lists four prevention uses: nausea and vomiting with highly emetogenic chemotherapy including cisplatin at 50 mg per square metre or more; initial and repeat courses of moderately emetogenic chemotherapy; radiotherapy (total body irradiation, a single high-dose fraction to the abdomen, or daily fractions to the abdomen); and prevention of postoperative nausea and/or vomiting. The UK SmPC for tablets lists management of nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy, and prevention of post-operative nausea and vomiting, adding that for established post-operative vomiting the injection is recommended.

The US Zofran injection label covers prevention of nausea and vomiting with initial and repeat courses of emetogenic chemotherapy from 6 months of age, and prevention of postoperative nausea and vomiting from 1 month of age. The WHO Model List of Essential Medicines, which has carried ondansetron since 2009 and recommends it also for children above 1 month, gives the indication as "nausea or vomiting".

Motion or travel sickness is not among the indications on the US or UK labels, and the UK SmPC states that the role of ondansetron in opiate-induced vomiting is not yet established. MedlinePlus notes that ondansetron is sometimes used outside the labelled uses for pregnancy sickness and other causes of vomiting, and the MHRA has described that off-label second-line role in severe vomiting of pregnancy; a doctor decides such use after weighing risks and benefits.

Dose as stated in the labels

All dose figures below are quoted from the US FDA and UK eMC labels, which name their own regimens; they are not Indian prescribing text, and India-specific approved prescribing text was not retrieved for this page. Prescription medicines must be taken only in the dose and for the period your doctor prescribes, and never on the basis of a website.

Adults — as stated in the US FDA label

• Highly emetogenic chemotherapy: the label states a single 24 mg dose given 30 minutes before the start of single-day highly emetogenic chemotherapy, including cisplatin 50 mg per square metre or more. The largest single oral dose in any labelled US regimen is 24 mg.
• Moderately emetogenic chemotherapy: the label states 8 mg 30 minutes before chemotherapy, a second 8 mg dose 8 hours after the first, then 8 mg twice a day (every 12 hours) for 1 to 2 days after chemotherapy ends.
• Radiotherapy: 8 mg 1 to 2 hours before each fraction for total body irradiation; for a single high-dose abdominal fraction 8 mg 1 to 2 hours before and then 8 mg every 8 hours for 1 to 2 days after; for daily fractionated abdominal radiotherapy 8 mg 1 to 2 hours before and 8 mg every 8 hours on each day of radiotherapy.
• Postoperative nausea and vomiting: the label states 16 mg given 1 hour before induction of anaesthesia.

Adults — as stated in the UK SmPC

• Emetogenic chemotherapy or radiotherapy by mouth: 8 mg taken 1 to 2 hours before treatment, then 8 mg every 12 hours for a maximum of 5 days to guard against delayed or prolonged vomiting.
• Highly emetogenic chemotherapy: a single dose of up to 24 mg with 12 mg oral dexamethasone sodium phosphate 1 to 2 hours before chemotherapy.
• Prevention of post-operative nausea and vomiting: 16 mg orally 1 hour before anaesthesia.
• Injection, adults: 8 mg slow intravenous injection (not less than 30 seconds) or intramuscular immediately before emetogenic chemotherapy or radiotherapy, followed by 8 mg orally every 12 hours; for post-operative nausea and vomiting 4 mg intramuscular or slow intravenous.

Children — as stated in the labels

The US oral label states 8 mg for children 12 to 17 years on moderately emetogenic chemotherapy, given 30 minutes before, a further 8 mg 8 hours later, then 8 mg twice a day for 1 to 2 days after; for children 4 to 11 years it states 4 mg 30 minutes before chemotherapy, further 4 mg doses 4 and 8 hours after the first dose, then 4 mg three times a day for 1 to 2 days. The UK SmPC dosing for children 6 months to 17 years is set by body surface area or by body weight, with the total dose over 24 hours never exceeding the adult dose of 32 mg; the treating doctor works this out.

Timing, food and missed doses

The UK SmPC states that tablets are swallowed whole with liquid, and the FDA label notes that food slightly increases bioavailability. The labels place the dose before the trigger — 30 minutes to 2 hours before chemotherapy or radiotherapy, and 1 hour before anaesthesia — so the usual adult dose stated in the label is timed around the procedure, and your doctor will tell you exactly when to take your pack. MedlinePlus advises that a missed dose be taken as soon as it is remembered, skipped if the next dose is nearly due, and never doubled.

Two labelled adjustments are worth noting for pharmacists: the US label limits the total daily dose to 8 mg in severe hepatic impairment and requires no change in renal impairment or in the elderly, while the UK SmPC caps the total daily dose at 8 mg in moderate or severe hepatic impairment. The US label also says tablets, ODT and oral solution may be used interchangeably at corresponding doses.

Side effects of ondansetron

The most common side effects on the labels are headache, constipation and a feeling of warmth or flushing, and serious reactions such as heart rhythm changes, severe allergic reactions and serotonin syndrome need urgent medical help. As with any medicine, tell the prescribing doctor about any reaction that is severe or does not settle.

The same label reports that after a single 24 mg dose before highly emetogenic chemotherapy, headache occurred in 11% and diarrhoea in 4% of 300 adults. With radiotherapy, headache, constipation and diarrhoea were each reported in 2% or more of patients. After a single 16 mg postoperative dose (n=550 versus 531 on placebo), the label records headache 9% versus 5%, hypoxia 9% versus 7%, fever 8% versus 6%, dizziness 7% versus 6%, urinary retention 5% versus 3% and itching 5% versus 4%.

The UK SmPC uses frequency bands: headache is very common (1 in 10 or more), and a sensation of warmth or flushing and constipation are common (1 in 100 to 1 in 10). Uncommon effects (1 in 1,000 to 1 in 100) include seizures, movement disorders such as dystonic reactions and oculogyric crisis, arrhythmias, chest pain, slow heartbeat, low blood pressure, hiccups and a symptom-free rise in liver tests. Rare effects (1 in 10,000 to 1 in 1,000) include serious immediate hypersensitivity including anaphylaxis, dizziness during rapid intravenous injection, transient visual disturbances and QTc prolongation including Torsade de Pointes; transient blindness is very rare and has mainly been seen with intravenous use.

Reactions that need urgent medical help

• Heart rhythm problems: ECG changes including QT prolongation have been seen and post-marketing cases of Torsade de Pointes reported. The effect is dose dependent; in a study of 58 healthy adults, a 32 mg intravenous infusion raised QTcF by a maximum mean of 19.5 ms versus placebo, while 8 mg raised it by 5.6 ms, and the label states that an 8 mg intravenous dose infused over 15 minutes did not prolong QT to a clinically relevant extent.
• Serotonin syndrome: reported with 5-HT3 antagonists alone but mostly with other serotonergic medicines, and some cases were fatal. Signs given in the label are agitation, hallucinations, delirium, coma, fast heartbeat, unstable blood pressure, sweating, flushing, fever, tremor, rigidity, muscle jerks and seizures, with or without vomiting or diarrhoea.
• Severe allergic reactions: anaphylaxis and bronchospasm have been reported, including in people who reacted to other 5-HT3 blockers; the medicine is stopped and treatment given promptly if this is suspected.
• Myocardial ischaemia, mainly with intravenous use, and masking of progressive ileus or stomach distension after abdominal surgery, are listed warnings.

MedlinePlus advises patients to tell the doctor about severe or persistent headache, constipation, weakness, tiredness, drowsiness or chills, and to seek urgent care for blurred vision or vision loss, rash, hives, swelling or breathing trouble, chest pain, fainting, a fast, slow or irregular heartbeat, agitation, confusion, hallucinations, fever, heavy sweating, stiff or twitching muscles or seizures. In overdose there is no specific antidote and treatment is supportive; children who swallowed more than 5 mg/kg developed signs consistent with serotonin syndrome on the US label.

Who should not take ondansetron, and key interactions

Both the US and UK labels contraindicate ondansetron in people with known hypersensitivity to ondansetron or any ingredient of the product, and in patients taking apomorphine, because of profound hypotension and loss of consciousness. Tell your doctor about every medicine, supplement and health condition before the first dose.

Heart and other cautions

• Congenital long QT syndrome: avoid. With electrolyte problems, congestive heart failure, slow heart rhythms or other QT-prolonging medicines, the UK SmPC advises caution and the US label advises ECG monitoring, and low potassium or magnesium should be corrected before the medicine is given.
• The UK SmPC names examples where the risk may rise: anthracyclines such as doxorubicin and daunorubicin, trastuzumab, erythromycin, ketoconazole, amiodarone and beta blockers such as atenolol or timolol.
• Liver-toxic medicines: children on such chemotherapy should be watched for liver problems, and the labels list a symptom-free rise in liver tests.
• Bowel obstruction: signs of subacute intestinal obstruction should be monitored, because ondansetron increases large-bowel transit time; after adenotonsillar surgery it may mask occult bleeding.
• Phenylketonuria: mouth-dissolving tablets contain aspartame. The US label states each 4 mg or 8 mg ODT has less than 0.03 mg phenylalanine, and the UK 4 mg ODT contains 3 mg aspartame.

Serotonergic medicines and tramadol

The US label names SSRIs, SNRIs, MAO inhibitors, mirtazapine, fentanyl, lithium, tramadol and intravenous methylene blue as serotonergic medicines to be combined only with monitoring for serotonin syndrome. On tramadol the labels differ in detail: the US label says ondansetron may increase patient-controlled tramadol use and asks for monitoring of pain control, while the UK SmPC says small studies suggest ondansetron may reduce tramadol's pain relief. Strong CYP3A4 inducers such as phenytoin, carbamazepine and rifampin lower ondansetron blood levels, and the US label recommends no dose change. Specific studies cited in the UK SmPC found no interaction with alcohol, temazepam, furosemide, alfentanil, morphine, lidocaine, thiopental or propofol.

Pregnancy

Ondansetron is not proven safe in pregnancy, and the three main regulators read here word the risk differently. The MHRA Drug Safety Update of 27 January 2020 reports a small increased risk of cleft lip and/or cleft palate with first-trimester use — 3 additional cases per 10,000 births, 14 versus 11 per 10,000 — with no increase in overall congenital malformations combined, and it advises counselling on benefits and risks with the decision made jointly with the woman. The EU-derived wording in the UK eMC SmPC states that ondansetron should not be used during the first trimester and that women of childbearing potential should consider contraception, and the EMA PRAC recommendation of 11 July 2019 put that wording into EU product information. The US label says published studies are inconsistent and too limited to judge safety; one cohort of 1.8 million US Medicaid pregnancies found a relative risk of oral clefts of 1.24 (95% CI 1.03 to 1.48) with first-trimester oral ondansetron and 0.95 (0.63 to 1.43) with intravenous use.

Breastfeeding

The labels do not agree. The US label states that clinically relevant exposure to the infant is unlikely at intravenous doses up to 4 mg per day, citing a study of 80 lactating mothers and 20 infants with low milk levels and no adverse effects attributed to the medicine. The UK SmPC, noting that ondansetron passes into the milk of lactating animals, recommends that mothers receiving ondansetron should not breastfeed.

Ondansetron rules in India

Ondansetron is on India's National List of Essential Medicines 2022 and its retail price is limited by NPPA ceiling prices, and pharmacy listings mark Indian ondansetron brands "prescription required". The points below are only what the cited government sources state; the current legal prescription schedule for ondansetron in India was not verified for this page.

• NLEM 2022 lists ondansetron in section 7.4.14 (anti-cancer agents, immunosuppressives and palliative care medicines) at levels of healthcare S and T — tablet 4 mg, tablet 8 mg, oral liquid 2 mg/5 mL and injection 2 mg/mL — and again in section 17.2.3 (antiemetics) with tablet 4 mg, oral liquid 2 mg/5 mL and injection 2 mg/mL. Domperidone and metoclopramide are the other NLEM antiemetics.
• The NPPA list headed "Therapeutic Category Wise Ceiling Price List" for anti-cancer formulations, footnoted as on March 2026, gives: oral liquid 2 mg/5 mL at ₹1.29 per mL, tablet 4 mg at ₹5.26 per tablet, injection 2 mg/mL at ₹6.10 per mL and tablet 8 mg at ₹9.28 per tablet.
• Simple arithmetic on those per-unit ceilings gives ₹52.60 for 10 tablets of 4 mg, ₹92.80 for 10 tablets of 8 mg, ₹38.70 for 30 mL of syrup and ₹12.20 for one 2 mL ampoule. Whether NPPA ceiling prices include or exclude GST was not confirmed, so treat these pack figures as arithmetic only and check the current NPPA wording. Brands may price below but not above the ceiling.
• NPPA ceiling prices are revised yearly from 1 April with the wholesale price index, so the March 2026 figures may have moved after 1 April 2026; check the current NPPA list before relying on a rupee figure.
• On prescription status: the CDSCO-hosted Drugs and Cosmetics Rules 1945 compilation read does not list ondansetron by name in the Schedule H table, and a later amendment may exist, so this page does not state a legal schedule. E-pharmacy listings mark Indian ondansetron brands "prescription required", and the medicine must be used only as a doctor prescribes.
• Globally, ondansetron has been on the WHO Model List of Essential Medicines since 2009; the current 2025 list carries the injection 2 mg/mL, oral liquid 4 mg/5 mL and solid oral 4 mg and 8 mg forms.

Commonly listed ondansetron brands in India

The brands listed in the table above are the ondansetron products that are widely stocked on a large Indian e-pharmacy and appear there as substitutes of one another; no published sales ranking naming ondansetron brands was found, so this is not a ranking and no brand is called best-selling. The 4 mg branded strips in that table range from ₹48.42 to ₹55.23; how those MRPs sit against the NPPA ceiling after GST was not confirmed here, and the listing site itself notes that MRP may vary by batch.

The Vibcare range of ondansetron

Vibcare supplies ondansetron 4 mg as mouth-dissolving tablets in 10x10 alu-alu packs across four brands — Ondanor MD 4 (Medanor), Vomijem MD 4 (Auspin), Vomiver MD 4 (Evermed) and Vomivib MD 4 (Prima) — and ondansetron 2 mg as three oral liquids and three injections across the Auspin, Evermed and Prima divisions.

The full range is available to Vibcare PCD franchise partners, with one partner appointed per district and monopoly rights confirmed in writing.

Frequently asked questions

Sources

Related reading

• Amoxicillin and potassium clavulanate: uses and brands
• Cold tablets in India: what they contain
• PCD pharma franchise with Vibcare
• Browse the Vibcare product range