Ondansetron
Ondansetron (on DAN se tron) is a generic medication prescribed for nausea and vomiting in certain situations. Ondansetron belongs to a group of drugs called serotonin antagonists.
Ondansetron (on DAN se tron) is a generic medication prescribed for nausea and vomiting in certain situations. Ondansetron belongs to a group of drugs called serotonin antagonists.
- Generic
- • Tablet
- • 4mg
- • 30 Tablets
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Introduction
Written by Jen Seabright, PharmD
Medically reviewed by Victor Nguyen, PharmD, MBA
Updated on June 28, 2023
The Food and Drug Administration (FDA) has approved ondansetron for prevention of nausea and vomiting due to:
- certain types of radiation therapy in adults
- anesthesia with surgery in adults and some children
- chemotherapy that is likely to cause nausea and vomiting in adults and some children
These approved uses differ based on the form of ondansetron your doctor prescribes.
This article describes ondansetron’s uses, side effects, and more. You’ll also find some coupon options to help save on the cost of ondansetron.
This article doesn’t provide coupons for all forms of ondansetron. To find coupons for ondansetron orally disintegrating tablet (ODT),* see this article.
* This type of tablet dissolves on or under your tongue.
Uses of ondansetron
The Food and Drug Administration (FDA) approves prescription drugs such as ondansetron for certain conditions. Approved uses for ondansetron are described below. These uses differ based on the form of ondansetron prescribed.
Use for nausea and vomiting
Doctors may prescribe ondansetron to help prevent nausea and vomiting due to chemotherapy. For this purpose, all forms of ondansetron may be used in adults.
Certain children may use some forms of ondansetron to help prevent these chemotherapy side effects:
- Children ages 4 years and older may take the oral tablets, orally disintegrating tablets (ODTs),* or oral solution.
- Children ages 6 months and older may receive the solution for intravenous (IV) infusion or intramuscular injection.†
Doctors may also prescribe ondansetron to help prevent nausea and vomiting after surgery due to use of anesthesia. For this purpose, all forms may be used in adults. The solution for IV infusion or intramuscular injection† may also be used for this purpose in children ages 1 month and older.
To help prevent nausea and vomiting due to radiation therapy, doctors may prescribe ondansetron oral tablets, ODTs,* or oral solution. It’s used for this purpose in adults.
For all uses described above, ondansetron is usually prescribed as a short-term treatment.
With nausea and vomiting, you feel queasy and may throw up. Other symptoms include sweating, loss of appetite, stomach cramps, and dizziness.
* These are tablets that dissolve on or under your tongue.
† An IV infusion is an injection given over time into a vein. An intramuscular injection is an injection given into a muscle.
Side effects of ondansetron
Ondansetron may cause mild or serious side effects. More common mild side effects of ondansetron and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.
To learn more about ondansetron’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for ondansetron listed in the “Article resources” section.
Mild side effects
More common mild side effects reported with some forms of ondansetron are listed below. These side effects may differ based on the form of ondansetron you use.
This article doesn’t include all possible mild side effects of the drug. To learn more about ondansetron’s side effects based on the form, refer to the prescribing information for ondansetron listed in the “Article resources” section.
With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.
Mild side effects of ondansetron oral tablet include:
- headache
- diarrhea
- fatigue (low energy)
- constipation
- mild allergic reaction*
Mild side effects of ondansetron solution for intravenous (IV) infusion or intramuscular injection† include:
- diarrhea
- headache
- fever
- constipation
- mild allergic reaction*
* For details about this side effect, see the “Interactions and warnings for ondansetron” section.
† An IV infusion is an injection given over time into a vein. An intramuscular injection is an injection given into a muscle.
Serious side effects
Serious side effects of ondansetron are listed below. These side effects may differ based on the form of ondansetron you use.
This article doesn’t include all possible serious side effects of the drug. To learn more about ondansetron’s side effects based on the form, refer to the prescribing information for ondansetron listed in the “Article resources” section.
With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.
In general, ondansetron’s serious side effects include:
- extrapyramidal symptoms, which affect movement
- chest pain, which could be a sign of a heart attack
- long QT syndrome
- serotonin syndrome (a condition caused by high levels of a brain chemical called serotonin)
- low potassium level
- severe allergic reaction†
* For details about this side effect, see the “Interactions and warnings for ondansetron” section.
Interactions and warnings for ondansetron
Below you’ll find information about ondansetron’s possible interactions and warnings.
Interactions of ondansetron
Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.
Before you use ondansetron, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:
- prescription or over-the-counter drugs
- vitamins, herbs, or supplements
To learn about drug-condition interactions, see the “Warnings for ondansetron” section just below.
Warnings for ondansetron
Ondansetron should not be used by certain people.
Ondansetron could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether ondansetron is a safe option for you. These warnings may differ based on the form of ondansetron you take.
Ask your doctor about specific warnings for ondansetron, and be sure to tell your doctor about your:
- current health, including any allergies to medications
- past health conditions or surgeries
Allergic reaction
Ondansetron can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.
If you’ve had an allergic reaction to ondansetron or any of its ingredients, your doctor will likely not prescribe ondansetron. They can tell you about medications that are safer options for you.
A mild allergic reaction may cause the following symptoms:
A severe allergic reaction may cause the following symptoms:
- swelling under your skin, usually in your hands, feet, eyelids, or lips
- swelling of your mouth, throat, or tongue, which can cause breathing problems
If you have an allergic reaction to ondansetron, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.
Overdose of ondansetron
If you take ondansetron by mouth, you should not take more ondansetron than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.
If you think you’ve taken too much ondansetron, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.
Pregnancy or breastfeeding and ondansetron
Information about ondansetron and pregnancy and breastfeeding is described below.
Ondansetron and pregnancy
It’s not known whether ondansetron should be used during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before using this medication.
Ondansetron and breastfeeding
It’s not known whether ondansetron should be used while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before using this medication.
Common questions about ondansetron
Below you’ll find answers to a few commonly asked questions about ondansetron.
What is ondansetron’s mechanism of action? How does the drug work?
“Mechanism of action” means how a drug works. Ondansetron works by blocking certain receptors of a substance called serotonin in the body. When serotonin binds to these receptors, nausea and vomiting can occur. The drug starts working about 30 minutes after you take a dose.
If you’d like to know more about how ondansetron works, talk with your doctor or pharmacist.
Can ondansetron cause long-term side effects?
No, long-term side effects aren’t likely with ondansetron. Ondansetron is used short term to prevent nausea and vomiting.
Studies didn’t report long lasting side effects occurring after treatment ended. (For details of these studies, refer to the prescribing information for ondansetron listed in the “Article resources” section.)
Talk with your doctor if you have questions about possible long-term side effects with ondansetron.
What to ask your doctor
This article describes ondansetron’s uses and side effects, ways to save on cost, and more. Let your doctor know if you have questions about ondansetron or would like more details about it.
Here’s a list of some possible questions you may want to ask your doctor:
- Do I have a high risk of side effects with ondansetron?
- Are there any alternative medications that I can take for my nausea?
- Does ondansetron interact with any of the medications I currently take?
Article resources
- Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm
- Ondansetron hydrochloride solution, for oral use. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/f4bad0ab-c501-4728-b3be-9c620e8568fd/spl-doc
- Ondansetron injection, USP for intravenous or intramuscular use. (2017). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/6a265130-d344-5744-e053-2a91aa0a8955/spl-doc
- Ondansetron orally disintegrating tablets. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/d11a99e2-3af2-4f6c-b0bb-1edd1ece135c/spl-doc
- Ondansetron tablets USP, for oral use. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/4ae18cf9-450f-4b42-a11e-8506b5783f02/spl-doc
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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