Zofran® (Ondansetron) Medication Guide
Oral Tablet

How Zofran® (Ondansetron) Works

Zofran® (ondansetron) is classified as an antiemetic medication, primarily used to alleviate nausea and vomiting caused by various conditions or medications. It works by blocking the action of serotonin, a natural substance in the body that can trigger nausea and vomiting.

Dosing and Storage Instructions

  • Take Zofran® (ondansetron) at the prescribed dosage and appropriate interval as indicated on your prescription bottle. 
  • Store Zofran® (ondansetron) tablets at room temperature between 36°F and 86° (2°C and 30°C). Ensure the tablets are kept away from excessive light, moisture, and heat.
  • Keep Zofran® (ondansetron) tablets in their original packaging or in a closed prescription bottle to protect them from damage.
  • Avoid storing Zofran® (ondansetron) in the bathroom or near the kitchen sink, where moisture levels may be high.
  • Always keep Zofran® (ondansetron) and any other medications out of reach from children and pets.

What If I Miss a Dose of Zofran® (Ondansetron)?

  • Zofran® (ondansetron) is typically used on an as needed basis depending on when you feel nauseous.
  • If you are taking Zofran® (ondansetron) on a scheduled basis and miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. 
  • Do not double the dose to catch up. Taking excessive doses may lead to unwanted side effects.

When Should I Stop Taking Zofran® (Ondansetron)?

  • Follow the prescribed duration of Zofran® (ondansetron) treatment as recommended by your healthcare provider.
  • If you experience any unusual symptoms or side effects while taking Zofran® (ondansetron), contact your healthcare professional immediately.

Refilling Your Prescription & Communicating with Your Healthcare Provider

  • For the initial four to six months of the Sunrise program, refilling your prescription requires a monthly check-in with your Sunrise physician. During this check-in, your physician will evaluate your weight-loss progress and determine if any changes are needed.
  • The goal of the monthly check-in with your physician is to optimize your weight-loss progress while minimizing side effects. 
  • Every month, we will reach out via email during Week 3 to initiate your check-in with your physician. You can also initiate a check in via the Sunrise refill page.

When You Should Message Your Sunrise Physician

You are able to message your physician at any time through the Sunrise messaging portal. In addition, below are specific times you should reach out to your Sunrise physician:

  • Any time you experience severe side effects.
  • Any time you have been hospitalized with other medical conditions, or started new medications.
  • Any time your BMI is less than 27.

Common Side Effects of Zofran® (Ondansetron)

Please message your Sunrise physician if you are experiencing any adverse symptoms. Call 911 or go to an emergency room if you feel like you are experiencing a medical emergency.

  • Common side effects of Zofran® (ondansetron) may include headache, constipation, dizziness, drowsiness, or tiredness. If any of these symptoms persist or worsen, inform your healthcare provider promptly.

Who Should Not Take Zofran® (Ondansetron)?

  • Patients who have a known hypersensitivity or allergy to ondansetron or any components of the medication should not take Zofran® (ondansetron).
  • Discuss with your healthcare provider before taking Zofran® (ondansetron) if you are pregnant, planning pregnancy, or breastfeeding.


Allergic Reactions

  • Rarely, some people may have allergic reactions to Zofran® (ondansetron), which could cause severe symptoms like difficulty breathing or swelling. If you notice any unusual symptoms after taking Zofran® (ondansetron), stop using it and seek medical help immediately.

QT Prolongation

  • Zofran® (ondansetron) can sometimes affect your heart by changing the rhythm of your heartbeat, otherwise known as the QT interval. This can be more likely in people with certain heart conditions or those taking specific medications. Your Sunrise physician may check your heart with an ECG if they think it's necessary.

Serotonin Syndrome

  • Zofran® (ondansetron) might interact with other medications, leading to a condition called serotonin syndrome. This can cause a mix of symptoms like confusion, fast heart rate, sweating, and shakiness. It's essential to tell your Sunrise physician about all the medications you're taking to avoid this.


  • Some forms of Zofran® (ondansetron) contain a tiny amount of phenylalanine, which might be important for people with a condition called phenylketonuria. Make sure to talk to your Sunrise physician if you have this condition.
  • As a point of reference, Zofran® (ondansetron) orally disintegrating tablets contain less than 0.03 mg phenylalanine.

Remember to talk openly with your healthcare provider about any concerns or new symptoms you experience while taking Zofran® (ondansetron).

Additional Online Resources

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