Zofran is a brand-name medication that’s been discontinued. But its generic version, ondansetron, is still available in several forms.
Zofran (ondansetron) is approved by the Food and Drug Administration (FDA) to prevent nausea and vomiting as a result of:
- chemotherapy treatment
- radiation treatment
- anesthesia and other drugs used during surgery
Some doctors also prescribe it off-label for vomiting and nausea (morning sickness) during pregnancy. Off-label use is when doctors prescribe a drug for a purpose other than what it’s approved for.
You can take Zofran every 6 or 12 hours during treatment, but it depends on why you’re taking the drug and any other medications you may be taking.
How often can I take Zofran (ondansetron)?
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You should only take Zofran according to a doctor’s prescription. How often you can take it depends on the dosage and the form. In general, doctors recommend:
- Zofran oral: Initial dose is usually taken 30 minutes before chemotherapy, 1 hour before surgery, or 1 to 2 hours before radiation therapy begins. After the initial dose, you might take the medication 1 to 3 times per day during chemotherapy or radiation therapy and possibly for 1 to 2 days after treatment ends.
- Zofran injectable: The initial dose is given 30 minutes before chemotherapy or immediately before surgery. A healthcare professional might provide additional doses 4 and 8 hours after the first dose if you still have nausea.
Injectable forms of Zofran are intravenous (given into a vein), or intramuscular (given into a muscle). A healthcare professional will give you these forms of Zofran.
What is the dosage of Zofran (ondansetron)?
Your dosage also depends on why you’re taking Zofran.
The following table provides a dosing guideline. A doctor may recommend Zofran along with other prescription medications, so it’s important to follow your individual dosing instructions.
| Typical Zofran dosage | |
|---|---|
| For surgery | To prevent nausea and vomiting after surgery: • 8 milligrams (mg) every 12 hours (oral) • 4 mg every 12 hours (IV) |
| During chemotherapy | Some doctors recommend 8 mg every 6 hours of Zofran. The protocol might also involve alternating Zofran with other anti-nausea medications, so you take one of either drug every 3 hours. Before taking oral Zofran, a doctor might recommend waiting 24 to 36 hours after your treatment if your chemotherapy IV contains certain drugs like palonosetron (Aloxi). |
| During pregnancy | Zofran is not a first-line treatment for nausea and vomiting in pregnancy (morning sickness). But if other drugs don’t work, a doctor might recommend 4 mg every 8 hours orally. |
Ondansetron (Zofran) is FDA approved for use in children. The dosage depends on the child’s age, weight, and the form of the medication. Children may be given ondansetron as a tablet, oral solution, or injection. Here’s what dosing for a child typically looks like:
| Typical Zofran dosage by age | |
|---|---|
| For chemotherapy-related nausea and vomiting | Ages 4 to 11: 4 mg about 30 minutes before treatment, then another 4 mg at 4 and 8 hours after the first dose. Then, 4 mg is taken three times per day for 1 to 2 days. Ages 12 to 17: 8 mg about 30 minutes before treatment, then another 8 mg dose 8 hours later. After that, 8 mg is usually taken every 12 hours for 1 to 2 days. These doses are the same whether your child takes ondansetron as a tablet or a liquid. |
| For nausea and vomiting after surgery | Children over the age of 1 month can receive Zofran (ondansetron) by injection. Children who weigh less than 40 kilograms (kg) are typically given 0.1 mg per kg of body weight. The injection is given slowly over at least 30 seconds. Children who weigh more than 40 kg are usually given 4 mg by IV. |
If your child is prescribed Zofran (ondansetron), their doctor will recommend the dose and form that’s best for your child’s age and treatment plan.
Note: For reference, 1 kilogram (kg) is equal to about 2.2 pounds (lb).
What is the maximum dosage of Zofran (ondansetron) in 24 hours?
For adults, the maximum dosage of Zofran oral tablets is 24 mg per day.
If an adult is given Zofran intravenously (IV), no single dose should be more than 16 mg. For adults who have liver problems, no single dose should exceed 8 mg.
If you have questions about the maximum daily dosage of Zofran for your child, be sure to ask your child’s doctor for details.
Zofran (ondansetron)side effects
Oral forms of Zofran may cause some side effects, including:
- headache
- diarrhea
- fatigue (low energy)
- dry mouth
- constipation
Injectable Zofran may cause the same side effects, as well as itching or skin reactions at the injection site.
Taking too much Zofran can lead to an overdose. Signs of overdose include:
- sudden blindness or loss of vision for a short time
- dizziness or lightheadedness
- fainting
- irregular heartbeat
Zofran is not suitable if you also take apomorphine (Apokyn). You should also use caution if you have phenylketonuria (PKU), as one of the components of Zofran dissolving tablet can lead to neurological damage if you have this condition.
There have been several studies about the effects of Zofran on pregnancy. Research has so far found no connection between pregnancy issues and pregnancy loss.
The American College of Obstetricians and Gynecologists recommends treating pregnancy nausea and vomiting with pyridoxine (vitamin B6) or doxylamine (Unisom). If these don’t work, Zofran might be an alternative.
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Get free cardZofran (ondansetron) alternatives
If Zofran doesn’t work well for you, alternatives might include the following:
Serotonin (5-HT3) antagonists:
- granisetron (Kytril)
- dolasetron (Anzemet)
- palonosetron (Aloxi)
NK-1 receptor antagonists:
- aprepitant (Emend)
- rolapitant (Varubi)
- fosaprepitant (Emend)
Dopamine antagonists:
- prochlorperazine (Compazine)
- metoclopramide (Reglan)
A doctor might recommend anti-nausea drugs alone or in combination with other medications not on this list.
Summary
Although Zofran has been discontinued, its generic version, ondansetron, is still available. It is approved for treating nausea and vomiting after surgery or during chemotherapy and radiation during cancer treatment.
Depending on your doctor’s recommendation, you can take Zofran every 6 to 12 hours. The maximum daily dose of Zofran oral tablets for adults is 24 mg. If an adult is given Zofran through an IV, no single dose should be more than 16 mg. For adults with liver problems, no single dose should be more than 8 mg.