Zofran (injection)
Generic name: ondansetron (injection) [ on-DAN-se-tron ]
Brand name: Zofran injection
Drug class: 5HT3 receptor antagonists
The Zofran brand name has been discontinued in the U.S. If generic versions of this product have been approved by the FDA, there may be generic equivalents available.
What is ondansetron?
Ondansetron is used to prevent nausea and vomiting that may happen with certain cancer medicines (chemotherapy) in adults and children at least 6 months old.
Ondansetron is also used to prevent nausea and vomiting that may happen after surgery in adults and children at least 1 month old.
Ondansetron may be used for purposes not listed in this medication guide.
Ondansetron side effects
Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.
Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.
Seek emergency medical help if you have signs of a heart attack: chest pain that spreads to your jaw or shoulder, nausea, and sweating.
Zofran may cause serious side effects. Call your doctor at once if you have:
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severe stomach pain, bloating, constipation, or any change in bowel habits; or
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dizziness, feeling light-headed, fainting, slow, fast, or uneven heartbeats.
Common side effects of Zofran may include:
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diarrhea;
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fever; or
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.
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Warnings
Tell your doctor about all your other medicines. Some drugs should not be used with ondansetron.
Before taking this medicine
You should not use ondansetron if you are allergic to ondansetron or similar medicines (dolasetron, granisetron, palonosetron).
Some drugs should not be used with ondansetron. Your treatment plan may change if you also use apomorphine.
Tell your doctor if you have or have ever had:
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a heart rhythm disorder such as long QT syndrome (in you or a family member);
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an electrolyte imbalance (such as low blood levels of potassium or magnesium);
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congestive heart failure, slow heartbeats;
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obstruction in the stomach or intestines, a change in bowel habits;
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surgery on your stomach or intestines; or
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severe liver disease.
Tell your doctor if you also use stimulant medicine, opioid medicine, herbal products, or medicine for depression, mental illness, Parkinson's disease, migraine headaches, serious infections, or prevention of nausea and vomiting. An interaction with ondansetron could cause a serious condition called serotonin syndrome.
Tell your doctor if you are pregnant or breastfeeding.
How is ondansetron given?
Ondansetron is injected into a muscle, or into a vein. A healthcare provider will give you this injection.
Ondansetron is usually given before surgery, and in certain cases another dose may be given after surgery.
To prevent nausea and vomiting caused by chemotherapy, ondansetron is given 30 minutes before the start of chemotherapy. Additional doses may be given 4 and 8 hours after the first dose.
What happens if I miss a dose?
In a medical setting you are not likely to miss a dose.
What happens if I overdose?
In a medical setting an overdose would be treated quickly.
What should I avoid after receiving ondansetron?
Follow your doctor's instructions about any restrictions on food, beverages, or activity.
What other drugs will affect ondansetron?
Ondansetron can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.
Many drugs can affect ondansetron. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all other medicines you use.
Popular FAQ
Can you take ondansetron while pregnant?
Although ondansetron is not specifically approved by the FDA to treat nausea and vomiting during pregnancy (NVP), its use is common, and approximately 25% of pregnant women are prescribed ondansetron to treat NVP. Overall, studies show the use of ondansetron appears to be associated with an additional 3 instances of oral cleft defects (such as cleft lip or cleft palate) for every 10,000 women exposed to ondansetron during their first trimester. There may also be a very slight increased risk of a type of heart defect called a ventricular septal defect, but no apparent increased risk of other birth defects, miscarriage, or fetal death. Continue reading
How long before a meal should you take ondansetron?
If you are taking ondansetron for nausea that occurs with meals, then the standard tablet should be taken half an hour to 1 hour before meals, and the orally disintegrating tablet or oral soluble film can be taken 15 minutes before meals. However, if you are taking ondansetron for constant, all day nausea then it should be taken at regular intervals during the day as prescribed, with or without food.
How often can you take ondansetron?
You can take ondansetron more frequently initially, for example, if you are taking it to prevent or treat nausea of vomiting from chemotherapy you can take 4mg then follow up with another 4mg dose at 4 and 8 hours after the first dose. The following day you should only take it every 8 hours (3 times a day). If you continue taking ondansetron more frequently than this you are at higher risk of side effects such as constipation, headache, or heart effects.
How long does ondansetron take to work?
Oral ondansetron works quickly, usually within 30 minutes, but it can take up to two hours for the full effect. It’s taken before you receive medicines or procedures that might make you feel nauseous or cause vomiting. Oral doses are usually taken 30 minutes before chemotherapy, 1 hour before surgery, or 1 to 2 hours before radiation treatments. You may need extra doses. Your doctor will tell you exactly when to take your medication.
Does ondansetron make you sleepy?
Yes, ondansetron (Zofran) might make you feel sleepy or tired. Ondansetron injection for the treatment of post-operative nausea and vomiting has been reported to cause drowsiness or sedation in 8% of patients vs. 7% of those using a placebo (an inactive treatment). Malaise (generally feeling unwell) and fatigue (tiredness or lack of energy) have also been reported in 13% of patients (vs. 2% placebo) when it is used orally for the prevention of chemotherapy-induced nausea and vomiting.
More about Zofran (ondansetron)
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- Patient tips
- During pregnancy
- Generic availability
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- Drug class: 5HT3 receptor antagonists
- Breastfeeding
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Further information
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.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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