ONDANSETRON

Written By:P. Thirumal ReddyB. Pharm Reviewed By:Dr. Tejashwin AdigaMBBS

Last updated on 31 Mar 2026 | 09:31 AM (IST)

ONDANSETRON

Background and Date of approval ONDANSETRON

Ondansetron was first developed in England and approved for medical use by the FDA in 1991 to treat nausea and vomiting.

Uses of ONDANSETRON

Ondansetron is used to treat nausea and vomiting in patients which is caused by some treatments such as chemotherapy or radiotherapy for cancer and nausea and vomiting that occurs post-surgery.

How is ONDANSETRON administered?

Ondansetron is available in two different forms of injectable solution [IV] and oral tablets. Tablets are available in various different strengths: oral tablets - 4mg, 8 mg, 24mg. Oral disintegrating tablets- 4 mg, 8 mg, 24 mg. Your physician will decide the dosage of this injection based on the severity of your disease and other factors.

Side Effects of ONDANSETRON

Ondansetron, like many medications, can lead to side effects. It may cause common side effects such as Constipation, diarrhoea, Headache, Hypoxia, General tiredness or weakness However not everyone experiences these effects, but if you do, promptly inform your healthcare provider for guidance.

Warnings

It is not recommended to take ondansetron if you are allergic to ondansetron or any of its ingredients. It is also not recommended for children. Inform your doctor if you have any neurological, heart, liver, lung, or kidney problems before getting treated with ondansetron. It must be avoided in patients with prolonged QT interval. Ondansetron may increase the risk of serotonin syndrome when used in combination with other serotonergic medications, such as certain antidepressants. Always get a detailed overview of your medical history and the medication from your doctor before starting the treatment.

Precautions

Before receiving ondansetron in any available forms, inform your doctor if you are pregnant, planning pregnancy, or breastfeeding. The medication will be administered as needed, and it is crucial to consult your doctor for personalized guidance. If you have liver disorders, disclose them to your physician as the dosage must be adjusted.

Word of Advice

If you forgot to receive the injection, contact your healthcare professional and reschedule it as soon as you remember. Inform your physician immediately if you face any allergic reactions such as sudden wheezing and chest pain or tightness, swelling of the eyelids, face, lips, mouth, tongue, difficulty breathing, skin rashes, or temporary loss of vision after receiving this medicine. Do not stop taking this medicine unless your doctor tells you to. Your doctor will regularly do lab tests to check the effectiveness of the medicine.

Frequently Asked Questions

Q1.

Can Ondansetron be used for morning sickness during pregnancy?

Do not use Ondansetron during the first trimester of pregnancy. This is because this medicine can slightly increase the risk of a baby being born with a cleft lip and cleft palate (openings or splits in the upper lip or the roof of the mouth). If you are already pregnant, think you might be pregnant, or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

Q2.

What are the possible serious side effects associated with Ondansetron?

The serious side effects of Ondansetron are the injection site reactions, abnormal heartbeat and allergic reactions such as sudden wheezing and chest pain or tightness, swelling of the eyelids, face, lips, mouth tongue, difficulty breathing, skin rashes, and temporary loss of vision.

Q3.

How long does it take for Ondansetron to work?

Ondansetron usually starts working within 30 minutes to 2 hours after taking a dose. The exact timing may vary depending on individual factors and the underlying condition being treated.

Q4.

Can I drive or operate machinery while taking Ondansetron?

Ondansetron is generally not associated with sedative effects or impairment of cognitive function. However, individual responses may vary. It is advisable to assess your personal reaction to the medication before driving or operating machinery, especially if you experience any dizziness or drowsiness.

Q5.

How does Ondansetron work?

Ondansetron is a selective serotonin 5-HT3 receptor antagonist. It works by blocking the action of serotonin, a neurotransmitter that triggers the vomiting reflex in the brain. By inhibiting serotonin, Ondansetron helps to prevent nausea and vomiting.

References

Aurobindo Pharma (Malta) Limited, Electronic Medicines Compendium (EMC), [Revised on January 2023] [Accessed on June 2023], https://www.medicines.org.uk/emc/files/pil.5222.pdf
GlaxoSmithKline, US Food & Drug Administration, [Revised on January 2023] [Accessed on June 2023], https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/020103s035_020605s019_020781s019lbl.pdf
Kenneth R. McQuaid, Drugs Used in the Treatment of Gastrointestinal Diseases, Lange’s Basic and Clinical Pharmacology, 14th Edition, 2018, 1087-1119

Disclaimer

The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.

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