Ondansetron Uses, Dosage, Side Effects & Warnings | DrugsAtlas
Authoritative Clinical Reference
Navigation
Therapeutic Class
Antiemetic
Subclass
5-HT3 (Serotonin) receptor antagonist
Speciality
Gastroenterology
Schedule (India)
Schedule H
Routes
Oral, Intravenous, Intramuscular
Formulations
- Tablets: 4 mg, 8 mg
- Orally Disintegrating Tablets (ODT): 4 mg, 8 mg
- Oral Solution/Syrup: 2 mg/5 mL
- Injection: 2 mg/mL (2 mL ampoule = 4 mg; 4 mL ampoule = 8 mg)
Adult indications
INDICATIONS + DOSING ā FOR CLINICIAN USE ONLY
Primary Indications (Approved / Standard in India)
1. Chemotherapy-Induced Nausea and Vomiting (CINV) ā Adults
A. Moderately Emetogenic Chemotherapy:
| Parameter | Recommendation |
|---|---|
| Starting dose | 8 mg orally or IV 30 minutes before chemotherapy |
| Titration | Not applicable |
| Usual maintenance dose | 8 mg orally every 8ā12 hours for 1ā2 days post-chemotherapy |
| Maximum dose | 24 mg/day orally; single IV dose not to exceed 16 mg |
B. Highly Emetogenic Chemotherapy (with dexamethasone):
| Parameter | Recommendation |
|---|---|
| Starting dose | 8 mg IV 30 minutes before chemotherapy (with dexamethasone 12ā20 mg IV) |
| Titration | Not applicable |
| Usual maintenance dose | 8 mg orally twice daily for 1ā2 days |
| Maximum dose | Single IV dose 16 mg; total daily dose 24 mg |
Clinical Notes:
- Always combine with dexamethasone for highly emetogenic regimens
- For multi-day chemotherapy, continue ondansetron for each treatment day plus 1ā2 days after
- NK1 receptor antagonist (aprepitant) may be added for highly emetogenic regimens if available
2. Postoperative Nausea and Vomiting (PONV) ā Adults
| Parameter | Recommendation |
|---|---|
| Starting dose (Prophylaxis) | 4 mg IV at induction of anaesthesia OR at end of surgery |
| Titration | Not applicable |
| Usual maintenance dose | Single dose usually sufficient; may repeat 4 mg if vomiting recurs |
| Maximum dose | 16 mg/day |
Treatment of Established PONV:
| Parameter | Recommendation |
|---|---|
| Dose | 4 mg IV as single dose |
| Repeat dosing | May repeat after 4ā6 hours if needed |
| Maximum dose | 16 mg/day |
Clinical Notes:
- More effective for preventing vomiting than nausea
- Consider combination with dexamethasone 4ā8 mg IV for high-risk patients
3. Radiotherapy-Induced Nausea and Vomiting ā Adults
| Parameter | Recommendation |
|---|---|
| Starting dose | 8 mg orally 1ā2 hours before each radiotherapy fraction |
| Titration | Not applicable |
| Usual maintenance dose | 8 mg orally twice daily on radiotherapy days |
| Maximum dose | 24 mg/day |
Clinical Notes:
- Higher doses may be required for total body irradiation or upper abdominal radiation
- Continue for 1ā2 days after completion of radiation if nausea persists
Secondary Indications ā Adults Only (Off-label)
| Indication | Dose | Duration | Supervision | Evidence Basis |
|---|---|---|---|---|
|
Hyperemesis Gravidarum ā OFF-LABEL
|
4ā8 mg orally TDS or 4 mg IV BD | Until symptoms controlled; short-term use preferred | Specialist only (Obstetrics) | Indian obstetric practice; use when first-line agents (doxylamine-pyridoxine, promethazine) fail |
|
Opioid-Induced Nausea/Vomiting ā OFF-LABEL
|
4ā8 mg orally or IV TDS | Duration of opioid therapy | General use acceptable | Palliative care protocols; clinical experience |
|
Pruritus in Cholestasis ā OFF-LABEL
|
4ā8 mg orally TDS | As required | Specialist only (Gastroenterology) | Limited evidence; Indian hepatology practice |
Paediatric indications''
PAEDIATRIC DOSING (Specialist Only)
Primary Indications
1. Chemotherapy-Induced Nausea and Vomiting
Age Restriction: Not recommended below 6 months of age except under specialist oncology supervision.
Intravenous Dosing:
| Body Weight | IV Dose (Single) | Timing | Maximum Single Dose |
|---|---|---|---|
| <10 kg | 0.1 mg/kg | 30 minutes before chemotherapy | ā |
| 10ā40 kg | 0.15 mg/kg OR 4 mg | 30 minutes before chemotherapy | 8 mg |
| >40 kg | 8 mg (adult dose) | 30 minutes before chemotherapy | 8 mg per dose |
Oral Dosing:
| Body Surface Area | Oral Dose | Frequency | Maximum Daily Dose |
|---|---|---|---|
| <0.6 m² | 2 mg | Every 12 hours for 1ā2 days | 4 mg/day |
| 0.6ā1.2 m² | 4 mg | Every 12 hours for 1ā2 days | 8 mg/day |
| >1.2 m² | 8 mg | Every 12 hours for 1ā2 days | 16 mg/day |
2. Postoperative Nausea and Vomiting
| Parameter | Recommendation |
|---|---|
| Starting dose | 0.1 mg/kg IV (maximum 4 mg) |
| Timing | At end of anaesthesia or when nausea occurs |
| Titration | Not applicable |
| Maximum dose | 4 mg per dose |
Clinical Notes:
- Single dose usually sufficient
- Slow IV administration over 2ā5 minutes preferred
- ECG monitoring if QT prolongation risk factors present
Secondary Indications ā Paediatric (Off-label)
| Indication | Age | Dose | Duration | Notes | Evidence Basis |
|---|---|---|---|---|---|
|
Acute Gastroenteritis with Vomiting ā OFF-LABEL
|
≥6 months | 0.15 mg/kg orally (max 4 mg) | Single dose; may repeat once after 8 hours | Use only in moderate-severe vomiting preventing oral rehydration | IAP guidelines; WHO supportive; multiple RCTs |
Important Restrictions:
- Not for routine use in mild viral gastroenteritis
- Should not replace oral rehydration therapy
- Assess for red flags (bilious vomiting, dehydration, altered sensorium) before prescribing
Age Restriction Statement:
Not recommended below 6 months of age except under specialist supervision (paediatric oncology/critical care).
Not recommended below 6 months of age except under specialist supervision (paediatric oncology/critical care).
Safety Monitoring:
- Monitor for QT prolongation in children with electrolyte disturbances
- Observe for constipation, especially with repeated dosing
- Watch for extrapyramidal symptoms (rare)
Renal Adjustments
No dose adjustment required in renal impairment (mild, moderate, or severe).
Dialysis:
- Haemodialysis: No supplemental dose required; ondansetron not significantly dialysed
- Peritoneal dialysis: No adjustment required
Note: Use with standard monitoring; metabolites may accumulate in severe renal impairment but clinical significance is unclear.
Hepatic adjustment
Contraindications
- Known hypersensitivity to ondansetron or other 5-HT3 receptor antagonists (granisetron, palonosetron)
- Concomitant use with apomorphine ā risk of profound hypotension and loss of consciousness
- Congenital long QT syndrome
Cautions
- Pre-existing QT interval prolongation or risk factors for QT prolongation
- Electrolyte abnormalities ā hypokalaemia, hypomagnesaemia (correct before use)
- Concomitant use of other QT-prolonging drugs
- Bradyarrhythmias or heart failure
- Hepatic impairment (reduced clearance)
- Subacute intestinal obstruction ā may mask symptoms
- Recent abdominal surgery ā may reduce lower GI motility
- Patients receiving other serotonergic drugs ā risk of serotonin syndrome
Pregnancy
| Parameter | Details |
|---|---|
| Risk category | Limited human data; some studies suggest possible increased risk of orofacial clefts with first-trimester use ā not definitively established |
| Preferred alternatives | First-line: Doxylamine + Pyridoxine combination; Second-line: Promethazine, Metoclopramide |
| When may be used | May be used when first-line agents fail; hyperemesis gravidarum refractory to other treatment; benefit must outweigh potential risk |
| Monitoring | Monitor maternal QT interval if used with other drugs; fetal growth monitoring as per standard antenatal care |
Lactation'
| Parameter | Details |
|---|---|
| Compatibility | Compatible with breastfeeding |
| Drug levels in milk | Low (estimated infant dose <5% of maternal weight-adjusted dose) |
| Preferred alternatives | Single-dose or short-term use preferred; domperidone or metoclopramide also options |
| Infant monitoring | Observe for drowsiness, constipation, feeding difficulties (rare) |
Elderly
| Parameter | Recommendation |
|---|---|
| Starting dose | 4 mg orally or IV; start at lower end of dosing range |
| Titration | Not typically required; assess response before increasing |
| Maximum dose | 16 mg/day preferred; avoid doses >16 mg/day |
| Special risks | Increased risk of QT prolongation; higher prevalence of electrolyte abnormalities; increased constipation risk; assess baseline ECG in cardiac patients |
Note: No specific pharmacokinetic changes in elderly with normal organ function, but increased sensitivity to adverse effects.
Major drug interactions
| Drug/Class | Mechanism/Effect | Recommendation |
|---|---|---|
| Apomorphine | Profound hypotension and loss of consciousness |
Contraindicated ā avoid combination
|
| Class IA antiarrhythmics (quinidine, procainamide) | Additive QT prolongation | Avoid combination; if unavoidable, ECG monitoring mandatory |
| Class III antiarrhythmics (amiodarone, sotalol) | Additive QT prolongation → risk of torsades de pointes | Avoid if possible; ECG monitoring if used together |
| Haloperidol, droperidol | QT prolongation risk | Use with caution; monitor ECG |
| High-dose methadone | Additive QT prolongation | Monitor ECG; correct electrolytes |
| Strong CYP3A4 inducers (rifampicin, phenytoin, carbamazepine) | Reduced ondansetron plasma levels → decreased efficacy | May need higher ondansetron dose or alternative antiemetic |
Moderate drug interactions
| Drug/Class | Effect | Recommendation |
|---|---|---|
| CYP3A4 inhibitors (ketoconazole, itraconazole, erythromycin, clarithromycin) | Increased ondansetron levels → increased QT risk | Monitor for adverse effects; consider dose reduction in hepatic impairment |
| SSRIs (fluoxetine, sertraline, paroxetine) | Possible serotonin syndrome; minor QT effect | Monitor for serotonin syndrome symptoms; usually safe in short-term use |
| SNRIs (venlafaxine, duloxetine) | Possible serotonin syndrome | Monitor as above |
| Tramadol | Ondansetron may reduce tramadol analgesic efficacy; serotonin syndrome risk | Monitor pain control; may need alternative analgesic |
| Dexamethasone | Used therapeutically together; no pharmacokinetic interaction | Standard combination for CINV prophylaxis |
| Loop/Thiazide diuretics | Hypokalaemia may increase QT prolongation risk | Monitor potassium levels |
| Fluoroquinolones (levofloxacin, moxifloxacin) | Additive QT prolongation | Use with caution; ECG if risk factors present |
- Headache (most common)
- Constipation
- Fatigue / asthenia
- Dizziness
- Flushing / warmth sensation
- Injection site reactions (pain, erythema with IV/IM)
- Diarrhoea (paradoxical)
- Transient visual disturbances
Serious Adverse effects
| Adverse Effect | Clinical Action |
|---|---|
| QT prolongation / Torsades de pointes | Discontinue immediately; ECG monitoring; correct electrolytes; manage arrhythmia |
| Serotonin syndrome | Discontinue ondansetron and other serotonergic drugs; supportive care; may require hospitalisation |
| Anaphylaxis / Severe hypersensitivity | Immediate discontinuation; emergency management |
| Stevens-Johnson Syndrome / TEN | Very rare; discontinue immediately; dermatology referral; hospitalisation |
| Transient blindness | Rare; typically resolves within 48 hours; reported mainly with IV use |
| Hepatotoxicity | Rare; usually mild transaminase elevation; discontinue if significant |
Monitoring requirements
Baseline:
- ECG in high-risk patients (elderly, cardiac disease, QT-prolonging drugs, electrolyte disturbances)
- Serum electrolytes (potassium, magnesium) in patients with risk factors
- Liver function tests if hepatic impairment suspected
After Initiation:
- Clinical response ā vomiting control, ability to tolerate oral intake
- Assess hydration status
- Monitor for constipation, especially with repeated dosing
- ECG if QT-prolonging drugs added or electrolyte abnormalities develop
Long-term (if used repeatedly):
- Periodic electrolyte monitoring
- Liver function tests if prolonged use
- Bowel function assessment
Brands in India
Single-Ingredient Formulations:
- Emeset (Cipla)
- Ondem (Alkem)
- Vomikind (Mankind)
- Zofran (GSK) ā originator brand
- Zondan (Dr. Reddy's)
- Onset (Sun Pharma)
- Emigo (Torrent)
- Emitron (FDC)
- Osetron (Cadila)
ODT Formulations:
- Emeset MD (Cipla)
- Ondem MD (Alkem)
Note: Fixed-dose combinations not commonly used; single-agent preferred for flexibility in dosing.
Price range (INR)
| Formulation | Approximate Price |
|---|---|
| Tablet 4 mg (per tablet) | ā¹2āā¹8 |
| Tablet 8 mg (per tablet) | ā¹4āā¹12 |
| ODT 4 mg (per tablet) | ā¹4āā¹10 |
| ODT 8 mg (per tablet) | ā¹6āā¹15 |
| Injection 4 mg/2 mL (per ampoule) | ā¹8āā¹25 |
| Injection 8 mg/4 mL (per ampoule) | ā¹15āā¹40 |
| Syrup 30 mL | ā¹15āā¹35 |
- Included in NLEM 2022
- NPPA price ceiling applicable
- Available through government supply for oncology programmes
Clinical pearls'
- Combine with dexamethasone for CINV ā ondansetron alone is less effective for highly emetogenic chemotherapy; combination significantly improves control
- IV dose ceiling of 16 mg ā single IV doses exceeding 16 mg associated with QT prolongation; older recommendations of 32 mg IV no longer supported
- Severe hepatic impairment ā maximum 8 mg/day due to reduced clearance and increased QT risk
- Paediatric gastroenteritis use is off-label but evidence-supported ā single oral dose can facilitate oral rehydration in children with persistent vomiting; not a substitute for ORS
- ODT formulation advantage ā dissolves on tongue without water; useful in patients with active vomiting or difficulty swallowing
- Constipation is common ā especially with repeated dosing; counsel patients and consider prophylactic laxatives in cancer patients on opioids
- No benefit over metoclopramide for simple nausea ā reserve for chemotherapy/radiotherapy/PONV; avoid routine use for non-specific nausea
Version
RxIndia v1.0 ā 05 Jun 2025
Reference
-
- CDSCO approved product inserts
- Indian Pharmacopoeia
- National List of Essential Medicines (NLEM) 2022
- API Textbook of Medicine
- IAP Drug Formulary
- AIIMS Antiemetic Protocols
- WHO Model List of Essential Medicines (paediatric supportive)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics (supportive)
- Published RCTs and meta-analyses for off-label paediatric gastroenteritis use
āļø
Clinical Responsibility
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
Content Feedback
Is this information helpful?
Help us improve our clinical database for the medical community.