Reviews (398)Overview: Ondansetron is used to reduce your chances of nausea and vomiting from radiation, chemotherapy, anesthesia, or surgery. It works in your gut and brain to reduce feelings of nausea. Common side effects may include headache, tiredness, constipation, or diarrhea. Serious side effects are less likely, but may include changes to your heart rhythm or a condition called serotonin syndrome. Contact your health care provider right away if you have a fast or skipping heartbeat or feel confused, anxious, or restless. Ondansetron is available in a tablet, orally disintegrating tablet, oral liquid, and injectable form. Before you start taking ondansetron, talk to your health care provider about all of your health conditions and any medicines you take.
Uses
What is ondansetron used for?
Ondansetron is commonly used to prevent nausea and vomiting that can happen when using medicines for cancer, radiation therapy, anesthesia, and after some types of surgeries.
Ondansetron may also be used for other conditions as determined by your health care provider.
How does ondansetron work (mechanism of action)?
Ondansetron blocks a specific receptor in the gut (intestines) and brain called 5-HT3 that normally causes nausea and vomiting when your body is exposed to certain substances, such as chemotherapy or anesthesia, or after surgery (especially on gut) or radiation treatment. By blocking this receptor, ondansetron reduces nausea and vomiting caused by chemotherapy, surgery/anesthesia, or radiation.
How is ondansetron supplied (dosage forms)?
Brands and other names
- Zofran
- Zofran ODT
- Zuplenz
Dosage forms and strengths
- 4 mg and 8 mg orally disintegrating tablets
- 4 mg/5 mL oral solution
- 4 mg, 8 mg, and 24 mg oral tablets
Ondansetron is also available in injectable forms.
How should I store ondansetron?
Ondansetron should be stored at room temperature between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place. Protect from light. Do not remove the orally disintegrating tablets from their blister pack until you are ready to take the medicine.
Side Effects
What are the most common side effects of ondansetron?
The most common side effects of ondansetron are listed below. Tell your health care provider if you have any of these side effects that bother you.
- Headache
- Tiredness
- Constipation/diarrhea
There may be other side effects of ondansetron that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of ondansetron?
While less common, the most serious side effects of ondansetron are described below, along with what to do if they happen.
Severe Allergic Reactions. Ondansetron may cause allergic reactions, which can be serious. Stop taking ondansetron and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching or skin rash
- Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Heart Rhythm Changes. Ondansetron may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk of this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take some medicines for other heart rhythm problems. Tell your health care provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.
Other Heart Problems. Ondansetron can cause poor blood flow to the heart, which is called myocardial ischemia. This can result in chest pain. Myocardial ischemia is more likely if you are given the IV form of ondansetron, or if you have existing heart disease. Do not take ondansetron if you have had a recent heart attack without talking to your health care provider. Get emergency help if you have any of the following symptoms of a heart attack.
- Chest pain or pressure
- Fast or abnormal heartbeat
- Trouble breathing
- Pain in your back, jaw, throat, or arm
- Sweating, upset stomach, vomiting, or dizziness
Serotonin Syndrome. Serotonin syndrome is when there is too much of a substance called serotonin in your body. Ondansetron can cause serotonin syndrome when it is taken alone or with other medicines that affect serotonin (see Interactions). This condition can be life-threatening. Get emergency help if you have any of the following symptoms of serotonin syndrome.
- Sweating, fever, or flushing
- Confusion
- Feeling agitated or restless
- Seeing or hearing unusual things
- Dizziness
- Fast or racing heartbeat
- Nausea, vomiting, or diarrhea
- Muscle twitching, stiffness, or tremor
- Seizures
Warnings & Precautions
Who should not use ondansetron?
Allergies to Ingredients. People who are allergic to any of the following should not take ondansetron.
- Ondansetron
- Zofran
- Zofran ODT
- Zuplenz
- Any of the ingredients in the specific product dispensed
Your pharmacist can tell you all of the ingredients in the specific ondansetron products they stock.
Drug Interactions. Ondansetron should not be used while you are using certain other medicines. Before taking ondansetron, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details
What should I know about ondansetron before using it?
Do not take ondansetron unless it has been prescribed to you by a health care provider. Take it as prescribed.
Do not share ondansetron with other people, even if they have the same condition as you. It may harm them.
Keep ondansetron out of the reach of children.
What should I tell my health care provider before using ondansetron?
Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if ondansetron is right for you.
In particular, make sure that you discuss any of the following.
Current and Past Health Conditions. Tell your health care provider if you have any of the following.
- Long QT syndrome
- Electrolyte problems (such as low potassium or low magnesium)
- Congestive heart failure
- Other heart rhythm problems (slow heartbeat/bradycardia)
Abdominal Surgery. Tell your health care provider if you have had recent surgery on your gut (stomach or intestines). In this case, as ondansetron prevents nausea and vomiting, it may be harder to knowif you are having complications from your surgery, such as any blockage, for example.
Phenylketonuria. Ondansetron orally disintegrating tablets may contain phenylalanine. If you have phenylketonuria or are not able to tolerate phenylalanine, talk to your health care provider before taking the orally disintegrating tablets.
Pregnancy. It is not known if or how ondansetron could affect pregnancy or harm a fetus. Tell your health care provider if you are or plan to become pregnant.
Breastfeeding. It is not known if ondansetron passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.
Interactions
Does ondansetron interact with foods or drinks?
There are no known interactions between ondansetron and foods or drinks.
It is unknown if drinking alcohol will affect ondansetron.
Does ondansetron interact with other medicines (drug interactions)?
Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you are using any of the following before taking ondansetron.
- Medicines within the past 2 weeks that can cause QT prolongation, which is a potentially dangerous heart rhythm problem
- A selective serotonin reuptake inhibitor (SSRI), which is a medicine commonly used for anxiety and depression
- A serotonin norepinephrine reuptake inhibitor (SNRI), which is a medicine commonly used for anxiety and depression
- A type of medicine called a triptan, such as sumatriptan (Imitrex and others), eletriptan (Relpax), and others, which is commonly used to treat migraines
- Apomorphine (Apokyn), which is a medicine commonly used for Parkinson’s disease
- Tramadol, which is a medicine used for pain
This may not be a complete list of medicines that can interact with ondansetron. Always check with your health care provider.
Overdose/Missed Dose
What should I do if I accidentally use too much ondansetron?
If you or someone else has used too much ondansetron, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
What should I do if I miss a dose of ondansetron?
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.
If you are being given ondansetron injections, be sure to make it to your appointment on time, as prevention of nausea and vomiting that occurs after radiation, chemotherapy, or surgery, requires that you are given your ondansetron at the right time.
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Ondansetron Hydrochloride
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