Health Information



ondansetron (injection)

Pronunciation: on DAN se tron

Brand: Zofran

What is the most important information I should know about ondansetron?

Multum donot

You should not use ondansetron if you are allergic to it, or if you are also using apomorphine (Apokyn).

You should not use this medication if you have a history of Long QT syndrome. Ondansetron can cause serious heart rhythm problems.

Before receiving ondansetron injection, tell your doctor if you have liver disease, heart disease, a heart rhythm disorder, congestive heart failure, or low potassium or magnesium levels in your blood.

Tell your doctor about all other medicines you use. There are many other medicines that can increase your risk of heart rhythm problems if you use them together with ondansetron.

Multum emt

Call your doctor at once if you have fast, slow, or uneven heartbeats, or if you feel like you might pass out.

What is ondansetron?

Ondansetron blocks the actions of chemicals in the body that can trigger nausea and vomiting.

Ondansetron injection is used to prevent nausea and vomiting that may be caused by surgery or medicine to treat cancer (chemotherapy).

Ondansetron injection may also be used for purposes not listed in this medication guide.

What should I discuss with my healthcare provider before taking ondansetron?

Multum donot

You should not use ondansetron if you are allergic to it, or if you are also using apomorphine (Apokyn).

Multum emt

Ondansetron can cause serious heart rhythm problems. You should not use this medication if you have a history of Long QT syndrome. Tell your doctor if anyone in your family has ever had this condition.

To make sure ondansetron is safe for you, tell your doctor if you have:

  • liver disease;
  • a serious heart condition or heart rhythm disorder;
  • slow or fast heartbeats, or heart block;
  • congestive heart failure;
  • an electrolyte imbalance (such as low levels of potassium or magnesium in your blood); or
  • if you are allergic to medicines similar to ondansetron, such dolasetron (Anzemet), granisetron (Kytril), or palonosetron (Aloxi).

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Multum nobrfeed

It is not known whether ondansetron passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

How should I take ondansetron?

Ondansetron is injected into a vein through an IV. You will receive this injection in a clinic or hospital setting.

Ondansetron is usually given just before your surgery begins, or within 2 hours after surgery.

To prevent nausea and vomiting caused by chemotherapy, ondansetron is given 30 minutes before the start of chemotherapy. A second and third dose of ondansetron are sometimes given 4 hours and 8 hours after the first dose.

Multum donot

Ondansetron injection is not for preventing nausea or vomiting that is caused by factors other than chemotherapy or surgery.

What happens if I miss a dose?

Since ondansetron is given by a healthcare professional, you are not likely to miss a dose.

What happens if I overdose?

Since this medication is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while taking ondansetron?

Multum dizzy

This medication may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

What are the possible side effects of ondansetron?

Multum emt

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Multum donot

Call your doctor at once if you have:

  • fast, slow, or uneven heartbeats;
  • feeling like you might pass out; or
  • headache with chest pain and severe dizziness, fainting, fast or pounding heartbeat.

Other common side effects may include:

  • diarrhea, constipation;
  • drowsiness;
  • itching, numbness, or tingling;
  • mild headache; or
  • fever, or cold feeling.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect ondansetron?

There are many other medicines that can increase your risk of heart rhythm problems if you use them together with ondansetron.

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with ondansetron, especially:

  • arsenic trioxide;
  • methadone;
  • tacrolimus;
  • tramadol;
  • an antibiotic such as clarithromycin, erythromycin, levofloxacin, moxifloxacin, or pentamidine;
  • an antidepressant such as amitriptyline, clomipramine, or desipramine;
  • anti-malaria medications such as chloroquine or mefloquine;
  • heart rhythm medicine such as amiodarone, dofetilide, disopyramide, dronedarone, ibutilide, procainamide, propafenone, quinidine, or sotalol;
  • other medicines to prevent or treat nausea and vomiting such as dolasetron or droperidol;
  • medicines to treat psychiatric disorders, such as chlorpromazine, clozapine, haloperidol, pimozide, thioridazine, or ziprasidone; or
  • migraine headache medicine such as sumatriptan or zolmitriptan.

This list is not complete. Other drugs may interact with ondansetron, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Where can I get more information?

Your doctor or pharmacist can provide more information about ondansetron injection.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2013 Cerner Multum, Inc. Version: 4.02. Revision date: 12/5/2012.

Your use of the content provided in this service indicates that you have read, understood and agree to the End-User License Agreement, which can be accessed by clicking on this link.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.