Ondansetron - Uses - Dosages - Side Effects - Precautions

Ondansetron: Frequently Asked Questions Answered

What Is Ondansetron?

Ondansetron is an antiemetic (anti-nausea) medication approved by the FDA to treat nausea and vomiting due to chemotherapy, radiation therapy, and surgery. Although not approved for other causes, Ondansetron has become the most used drug to prevent postoperative nausea and vomiting.

It acts by blocking a natural substance in our body called serotonin, which causes vomiting. It is available in the market as Zuplenz, Zofran, and Zofran ODT.

What are the uses of Ondansetron?

This medication is used alone or in combination with other medicines to treat:

  • Nausea and vomiting, associated with cancer chemotherapy (first-line treatment).
  • Nausea and vomiting, associated with radiotherapy (whole-body radiation or multiple radiations at different time fractions).
  • Postoperative nausea and/or vomiting.

Apart from this, its off-label label use includes preventing morning sickness associated with pregnancy. Ondansetron is used within pediatric populations to treat acute gastroenteritis and cyclic vomiting syndrome. However, there is little information available on its efficacy regarding these.

Studies also suggest that Ondansetron relieves some of the most intrusive symptoms of Irritable bowel syndrome with diarrhea.

Book Doctor Appointment
Book Online Doctor Appointment
Search Specialty Doctor
Health Packages

What are the possible side effects of Ondansetron?

Common side effects may include:

  • Headache.
  • Tiredness.
  • Drowsiness.
  • Diarrhea or constipation.

Get immediate medical help if you have symptoms of allergic reactions like rashes, hives, fever, chills, difficulty breathing, or swelling of face, tongue, lips, or throat.

Tell your doctor right away if you have any of these serious side effects:

  • Stomach pain or muscle spasm/stiffness.
  • Severe constipation or bloating.
  • Headache with chest pain and severe dizziness.
  • Fainting, and fast or pounding heartbeat.
  • Jaundice.
  • Vision changes (blurred vision or temporary vision loss).
  • Unusual agitation/restlessness.
  • Hallucinations.
  • Unexplained fever.
  • Fast heartbeat.
  • Severe nausea/vomiting/diarrhea.
  • Loss of coordination (caused due to high levels of serotonin in the body).

This is not an exhaustive list of adverse effects, and others may also occur. Consult our experts at Yashoda Hospitals for medical advice about the various side effects.


Frequently Asked Questions about Ondansetron

1. Is Ondansetron Safe In Pregnancy?

No. Few studies found the risk of birth defects (heart abnormalities and cleft palates) associated with Ondansetron use during the first trimester. Although the chance of having a baby with a birth defect is very low, Ondansetron exposure still may not be entirely safe for pregnant women due to the lack of sufficient clinical data. Nevertheless, it is one of the most commonly used agents for treating morning sickness during pregnancy. This could be because of its quickly dissolving formulation (ODT) and efficacy.

2. How Much Ondansetron Can I Give My Child?

The dosage is 0.15 mg/kg in liquid form (to a maximum dose of 8 mg). Weight-based oral dosing regimens are suggested for children aged =6 months. It should be given immediately before chemotherapy as a single intravenous (IV) dose over not less than 15 minutes. Oral doses can be given 12 hours later and may be continued for 5 days post-therapy.

3. What Not To Take With Ondansetron?

Do not use apomorphine and ZOFRAN together; this may cause a significant drop in your blood pressure and lead to loss of consciousness. Please report your medication history to the clinician before taking Ondansetron. Using Ondansetron and other serotonergic agents (like medications to treat migraines and depression) may lead to serotonin syndrome. Seek immediate medical care for symptoms such as agitation or restlessness, confusion, and other gastrointestinal symptoms (e.g., diarrhea).

4. Does Ondansetron Cause Constipation?

Constipation is one of the side effects associated with the use of Ondansetron. Some tips for dealing with constipation include drinking 8-10 glasses of non-alcoholic fluids a day, keeping the body active, and having fiber in your diet (fruits and vegetables). A stool softener once or twice a day may also prevent constipation. Please contact your clinician if you do not have a bowel movement for 2-3 days.

5. How Quickly Does Ondansetron Work?

The standard dosage form (ODT) will start to work within half an hour to 2 hours. For chemotherapy-induced nausea and vomiting, the drug should be administered at least 30 minutes before chemotherapy. An IV dose will start to work within 10 minutes after the administration of its injection.

6. Is Ondansetron A Narcotic?

No. Direct addiction studies on animals have shown that Ondansetron is not a benzodiazepine derivative, nor does it contain any narcotic side effects. Moreover, this medication is used to treat nausea and vomiting associated with opiate withdrawal. However, there are specific side effects of Ondansetron related to your central nervous system (such as drowsiness, headache, and dizziness).

7. What'S Better Cyclizine Or Ondansetron?

Both antiemetics are equally effective. Both reduce severe and moderate nausea. However, Ondansetron is a good choice when a great amount of tissue trauma is anticipated during surgeries. Cyclizine is a cheap antiemetic with demonstrated safety and efficacy. It is well suited for use in combination with other antiemetics such as Ondansetron.

8. Can You Take Ondansetron On An Empty Stomach?

Ondansetron can be taken with or without food. However, it works faster on an empty stomach, an hour before food, or 2 hours after meals. The first dose of Ondansetron is usually taken before the start of your surgery, chemotherapy, or radiation treatment. Follow your doctor's dosing instructions carefully while taking the medication.

9. Can Ondansetron Be Addictive?

No, this is not an addictive medication. It can be taken up to 3 times daily for 1-2 days after your chemotherapy/radiation or after surgery is finished. Take Ondansetron as per the prescribed schedule to get the most benefit from this medicine.

10. Is Ondansetron A Steroid?

No, it is not a steroid drug but is used as an antiemetic (anti-nausea). It belongs to a class of medications called 5-HT3 receptor blockers. Always consult your healthcare provider while taking Ondansetron with other medications, including steroids.

Get Free Second Opinion

Disclaimer: The information provided herein is accurate, updated and complete as per the best practices of the Company. Please note that this information should not be treated as a replacement for physical medical consultation or advice. We do not guarantee the accuracy and the completeness of the information so provided. The absence of any information and/or warning to any drug shall not be considered and assumed as an implied assurance of the Company. We do not take any responsibility for the consequences arising out of the aforementioned information and strongly recommend you for a physical consultation in case of any queries or doubts.