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Generic Name:

ondansetron, Orally disintegrating solid

All Brands

  • Zofran ODT
SECTION 1 of 4

Highlights for ondansetron

Orally disintegrating solid
1

Ondansetron is used to prevent nausea and vomiting caused by certain medical treatments. These treatments include chemotherapy, radiation treatment, or surgery.  

2

This drug comes in four forms that you take by mouth: a tablet, a disintegrating tablet, a solution, and  a film. It’s also available in an intravenous (IV) form. This form is only given by a healthcare provider.

3

All oral forms of ondansetron are available as brand-name drugs. The brand names are Zofran (tablet and solution), Zofran ODT (disintegrating tablet), and Zuplenz (film). The tablets and solution are also available as generic drugs.

4

The more common side effects of this drug include headache, diarrhea, constipation, drowsiness, and dizziness. 

5

Ondansetron may cause a life-threatening condition called serotonin syndrome. Symptoms of this serious side effect include agitation, hallucinations (seeing or hearing things that aren’t real), sweating, rapid heartbeat, and coma. 

IMPORTANT INFORMATION

Serotonin syndrome

Ondansetron raises your risk of a life-threatening condition called serotonin syndrome. This syndrome occurs when the chemical serotonin builds up too much in your body. A high level of serotonin  can cause agitation, delirium (confused thinking), and hallucinations (seeing or hearing things that aren’t real). It can also cause coma, muscle stiffness, tremor, seizures, sweating, and jerky muscle movements. Call your doctor right away if you have any of these symptoms. This condition can result from using ondansetron alone. But it’s more likely when you’re also taking another drug that affects serotonin levels.

What is ondansetron?

Ondansetron is a prescription drug. It comes in four forms that you take by mouth: a tablet, a disintegrating tablet, a solution, and a film. It’s also available in an intravenous (IV) form, which is only given by a healthcare provider.

All oral forms of ondansetron are available as brand-name drugs. They’re called Zofran (tablet and solution), Zofran ODT (disintegrating tablet), or Zuplenz (film). The tablets and oral solution are also available as generic drugs. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version. 

Ondansetron may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

Ondansetron can be used to prevent nausea and vomiting caused by certain medical treatments. These treatments include:

  • chemotherapy
  • radiation treatment
  • surgery

How it works

Ondansetron belongs to a class of drugs called antiemetics. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions. Antiemetics are drugs that reduce nausea and vomiting.

More Details

How it works

Ondansetron belongs to a class of drugs called antiemetics. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions. Antiemetics are drugs that reduce nausea and vomiting.

Ondansetron works by blocking the release of the chemical serotonin in the gut and the central nervous system. This keeps the serotonin from causing nausea and vomiting. 

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SECTION 2 of 4

ondansetron Side Effects

Orally disintegrating solid

More Common Side Effects

The more common side effects of ondansetron can include:

  • headache

  • diarrhea

  • constipation

  • dizziness

  • drowsiness

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following: 

  • Serotonin syndrome. Symptoms can include:

    • agitation
    • hallucinations (seeing or hearing things that aren’t real)
    • rapid heartbeat
    • sweating
    • feeling hot
    • muscle rigidity (stiffness)
    • tremor
    • nausea
    • vomiting
    • diarrhea
    • coma
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Ondansetron may cause drowsiness. 

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 4

ondansetron May Interact with Other Medications

Orally disintegrating solid

Ondansetron can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well. 

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Medications that might interact with this drug

Drugs you should not use with ondansetron

Do not take these drugs with ondansetron. Doing so can cause dangerous effects in your body. Examples of these drugs include: 

  • Apomorphine.
    • When used with ondansetron, this drug can cause your blood pressure to drop to unsafe levels. This can cause you to pass out.

Interactions that increase your risk of side effects

Side effects from ondansetron: Taking ondansetron with certain medications raises your risk of side effects from ondansetron. This is because the amount of ondansetron in your body may be increased. Examples of these drugs include: 

  • Other drugs that affect serotonin levels, such as fluoxetine or paroxetine.
    • Increased side effects can include drowsiness, headache, or stomach upset. Your doctor probably does not need to adjust the dose of ondansetron, but you should watch for side effects.

Interactions that can make ondansetron less effective

When used with ondansetron, these drugs can make ondansetron less effective. This is because the amount of ondansetron in your body may be decreased. Examples of these drugs include: 

  • Antiseizure drugs, such as phenytoin or carbamazepine.
    • Your doctor may switch you from ondansetron to a different drug to treat your nausea if needed.
  • Tuberculosis drugs, such as rifampin, rifabutin, or rifapentine.
    • Your doctor may switch you from ondansetron to a different drug to treat your nausea if needed.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Ondansetron warnings
heart arrhythmias
People with risk factors for heart arrhythmias

If you have conditions such as heart failure or congenital long QT syndrome, this drug may increase your risk of arrhythmias. Ask your doctor if you have risk factors for arrhythmias.

phenylketonuria
People with phenylketonuria

The ondansetron orally disintegrating tablets contain phenylalanine. This amino acid can cause dangerous effects in people with a condition called phenylketonuria. Don’t take the orally disintegrating tablets if you have phenylketonuria.

Pregnant women
Pregnant women

There haven’t been enough studies done in humans to be certain how ondansetron might affect a fetus when the mother takes it. Research in animals has not shown a risk to the fetus. However, animal studies do not always predict the way humans would respond. Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should only be used in pregnancy if clearly needed.

Women who are breast-feeding
Women who are breast-feeding

Ondansetron may pass into breast milk and may cause side effects in a child who is breastfed.

Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.

For seniors
For seniors

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. 

For children
For children

This medication has not been studied in children younger than 4 years. It should not be used in children of this age range. 

When to call the doctor
When to call the doctor

Call your doctor right away if you become pregnant while taking this drug.

Allergies
Allergies

Ondansetron can cause a severe allergic reaction. Symptoms can include:

  • flushing
  • trouble breathing
  • swelling of your throat or tongue
  • dizziness
  • coughing

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

SECTION 4 of 4

How to Take ondansetron (Dosage)

Orally disintegrating solid

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on: 

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Prevention of nausea and vomiting caused by chemotherapy

Generic: Ondansetron

Form: Oral tablet
Strengths: 4 mg, 8 mg, 24 mg
Form: Orally disintegrating tablet
Strengths: 4 mg, 8 mg
Form: Oral solution
Strengths: 4 mg/5 mL

Brand: Zofran

Form: Oral tablet
Strengths: 4 mg, 8 mg, 24 mg
Form: Oral solution
Strengths: 4 mg/5 mL

Brand: Zofran ODT

Form: Orally disintegrating tablet
Strengths: 4 mg, 8 mg

Brand: Zuplenz

Form: Oral film
Strengths: 4 mg, 8 mg
Adult dosage (ages 18–64 years)
  • Oral tablets and oral film
    • Typical dosage: 24 mg one time, 30 minutes before chemotherapy. 
  • All drug forms
    • Typical dosage: 8 mg, 30 minutes before chemotherapy, and another 8 mg, 8 hours later. After that, you can take 8 mg twice per day for 1–2 days.
Child dosage (ages 12–17 years)
  • Oral tablets and oral film
    • Typical dosage: 24 mg one time, 30 minutes before chemotherapy. 
  • All drug forms
    • Typical dosage: 8 mg, starting 30 minutes before chemotherapy. Eight hours later, your child can take another 8 mg. After that, 8 mg can be given twice per day for 1–2 days.
Child dosage (ages 4–11 years)
  • All drug forms
    • Typical dosage: 4 mg by mouth 3 times per day, starting 30 minutes before chemotherapy. For 1–2 days after chemotherapy, your child can take 4 mg by mouth, 3 times per day. 
Child dosage (ages 0–3 years)
  • All drug forms
    • It has not been confirmed that ondansetron is safe and effective for use in children younger than 4 years. It should not be used in children of this age range.
Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Special considerations

Liver disease: If you have severe liver disease, you should not take more than 8 mg of ondansetron per day.

Prevention of nausea and vomiting caused by radiation treatment

Generic: Ondansetron

Form: Oral tablet
Strengths: 4 mg, 8 mg, 24 mg
Form: Orally disintegrating tablet
Strengths: 4 mg, 8 mg
Form: Oral solution
Strengths: 4 mg/5 mL

Brand: Zofran

Form: Oral tablet
Strengths: 4 mg, 8 mg, 24 mg
Form: Oral solution
Strengths: 4 mg/5 mL

Brand: Zofran ODT

Form: Orally disintegrating tablet
Strengths: 4 mg, 8 mg

Brand: Zuplenz

Form: Oral film
Strengths: 4 mg, 8 mg
Adult dosage (ages 18–64 years)
  • All drug forms
    • Typical dosage: 8 mg three times per day, starting 1–2 hours before radiation. This may vary depending on the type of radiation you receive.
Child dosage (ages 0–17 years)
  • All drug forms
    • It has not been established that ondansetron is safe and effective for this use in children.
Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Special considerations

Liver disease: If you have severe liver disease, you should not take more than 8 mg of ondansetron per day.

Prevention of nausea and vomiting caused by surgery

Generic: Ondansetron

Form: Oral tablet
Strengths: 4 mg, 8 mg, 24 mg
Form: Orally disintegrating tablet
Strengths: 4 mg, 8 mg
Form: Oral solution
Strengths: 4 mg/5 mL

Brand: Zofran

Form: Oral tablet
Strengths: 4 mg, 8 mg, 24 mg
Form: Oral solution
Strengths: 4 mg/5 mL

Brand: Zofran ODT

Form: Orally disintegrating tablet
Strengths: 4 mg, 8 mg

Brand: Zuplenz

Form: Oral film
Strengths: 4 mg, 8 mg
Adult dosage (ages 18–64 years)
  • All drug forms
    • Typical dosage: 16 mg one hour before you receive anesthesia for surgery.
Child dosage (ages 0–17 years)
  • All drug forms
    • It has not been established that ondansetron is safe and effective for this use in children.
Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Special considerations

Liver disease: If you have severe liver disease, you should not take more than 8 mg of ondansetron per day.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Ondansetron comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

You could have nausea and vomiting that’s not controlled.

If you take too much

You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • faintness
  • drowsiness
  • agitation
  • fast heartbeat
  • flushing (sudden reddening of the skin)
  • seizures

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room right away.   

How to tell if the drug is working

You should not have nausea or vomiting. If you do, it should be less severe.

Ondansetron is used for short-term treatment.

Important considerations for taking ondansetron
take ondansetron with or without food
You can take ondansetron with or without food
timing
Take this drug at the time(s) recommended by your doctor
can cut or crush the ondansetron oral tablets
You can cut or crush the oral tablets. But you should not cut or crush the orally disintegrating tablets
storage
Store this drug carefully
See Details
medication may or may not be refillable
A prescription for this medication may or may not be refillable. Your doctor can tell you more
Travel
Travel
See Details
Self-management
Self-management
See Details
not usually stocked
Not every pharmacy stocks all formulations of this drug
See Details

Store this drug carefully

  • Store the oral tablets and orally disintegrating tablets at a temperature between 36°F and 86°F (2°C and 30°C).
  • Store the oral solution at a temperature between 59°F and 86°F (15°C and 30°C).
  • Store the oral film at a temperature between 68°F and 77°F (20°C and 25°C).
  • Keep this drug away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

Using the orally disintegrating tablet:

  • When taking the tablet out of its package, peel the foil back. Don’t try to push the tablet through the foil. This step will help keep the tablet from breaking.
  • Place the tablet on your tongue. Leave it there for a few seconds to allow it to dissolve, and then swallow. You don’t need to take the tablet with liquid.

Not every pharmacy stocks all formulations of this drug

When filling your prescription, be sure to call ahead.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.


Show Sources

Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by University of Illinois-Chicago, Drug Information Group on June 15, 2017

Disclaimer: Healthline 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 other 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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