Zofran Syrup (Ondansetron)

Generic equivalent: Ondansetron

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Ondansetron Syrup 4mg/5mL

Product of Canada
Manufactured by: Apotex Inc
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Ondansetron Syrup 4mg/5mL
Product of Canada
Manufactured by Apotex Inc
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Zofran (Ondansetron) Dosage and Side Effects

Doctors sometimes prescribe Zofran to treat nausea and vomiting caused by cancer treatments such as chemotherapy and radiation therapy.  Zofran also can treat nausea and vomiting after surgery.  The drug may also help prevent the common complication of shivering in people who have had anesthesia.

Proper Use of this medication

The label on the container of your medicine should tell you how often to take your medicine and how many doses you should take each time. If not, or if you are not sure, consult your doctor or pharmacist.

Do not take more doses, or take them more often than your doctor prescribes. If, however, you vomit within one hour of taking your medicine, you should take the same amount of medicine again. If vomiting persists, consult your doctor.

For ZOFRAN ODT orally disintegrating tablets:

Do not try to push ZOFRAN ODT through the lidding foil.

Tear along the perforations of the foil to separate off one tablet within its blister unit.

Peel back the foil at the place indicated by the arrow.

Gently push the ZOFRAN ODT out of the blister pocket, and remove it with dry fingers.

Place the ZOFRAN ODT on top of the tongue. It will dissolve very quickly.

Swallow as normal.

Usual dose:

Chemotherapy Induced Nausea and Vomiting:

Based on how likely you are to experience nausea and/or vomiting, caused by your cancer treatment, your doctor will tell you the amount you need to take and how frequently.

Adult: You may receive ZOFRAN before and/or after chemotherapy. The dose of ZOFRAN is between 8 and 24 mg a day (taken orally) for up to 5 days depending on the potential of your chemotherapy treatment to cause you to vomit and/or have nausea.

Children (4 to 12 years): After chemotherapy, take 4 mg orally every 8 hours for up to 5 days.

Radiotherapy Induced Nausea and Vomiting:

Adult: Take 8 mg orally 1 to 2 hours before radiotherapy. After therapy, take 8 mg orally every 8 hours for up to 5 days after a course of treatment.

Prevention of Post-Operative Nausea and Vomiting:

Adult: Take 16 mg orally one hour before anaesthesia.

If you have a liver problem, your dose may be altered. Please follow the instructions of your doctor.


In case of drug overdose, contact a health care practitioner, hospital emergency department or regional Poison Control Centre immediately, even if there are no symptoms.

Missed dose:

If you miss a dose and do not feel sick, take the next dose when it is due.

If you forget to take your medicine and feel sick or vomit, take a dose as soon as possible.

If your doctor decides to stop the treatment, do not keep any left over medicine unless your doctor tells you to.

Side Effects

You may experience headaches, a feeling of warmness, flushing or constipation, while taking ZOFRAN. Although uncommon, low blood pressure and hiccups have also been reported.

There is no need to stop taking your medicine, but you should tell your doctor about these symptoms at your next visit.

If your nausea (feeling of sickness) or vomiting do not improve while taking ZOFRAN, consult your doctor for further advice.

If you feel unwell or have any symptoms that you do not understand, you should contact your doctor immediately.

Warnings and Precautions

BEFORE you use ZOFRAN or ZOFRAN ODT talk to your doctor or pharmacist if:

  • you have a history of hypersensitivity (an allergic reaction) to any ingredient in ZOFRAN or ZOFRAN ODT.

  • if you have had an allergic reaction to medicines similar to ZOFRAN or ZOFRAN ODT such as medicines containing granisetron or palonosetron.

  • you are pregnant or likely to become pregnant.

  • you are breast feeding.

  • you have liver problems.

  • you have signs of intestinal obstruction.

  • you have a history of heart problems.

  • you have a condition called phenylketonuria and were prescribed ZOFRAN ODT, because it contains aspartame.

If you experience wheezing and tightness of the chest, heart throbbing, swelling of eyelids, face or lips, or develop a skin rash, skin lumps or hives, contact your doctor immediately. Do not take anymore medicine unless your doctor tells you to do so.

Serotonin Syndrome is a rare but potentially life-threatening reaction that may occur if you take ZOFRAN or ZOFRAN ODT with certain other medications. It may cause serious changes in how your brain, muscles and digestive system work. Be sure to tell your healthcare professional all the medicines you are taking.

Interactions with this medication

As with most medicines, interactions with other drugs are possible. To avoid potentially life-threatening reactions tell your healthcare professional about ALL the medications you take, including those prescribed by other doctors, vitamins, minerals, natural supplements or alternative medicines. It is important that your doctor know about all your medication so that you get the best possible treatment. Tell your doctor if you are taking carbamazepine, phenytoin, or rifampicin. If you are taking any medicines containing tramadol, ZOFRAN may decrease its effectiveness.

Also, make sure you tell your doctor or pharmacist if you are taking:

  • Drugs used to treat heart rhythm disorders

  • Other drugs that may disturb heart rhythm

  • Antipsychotics

  • Antidepressants

  • Antibiotics or antifungals

  • Opioid analgesics (painkillers)

  • Other drugs to treat nausea and vomiting

  • Asthma drugs

  • Cancer drugs

  • Diuretics

  • Other drugs that affect serotonin including SSRIs, SNRIs§, triptans, MAOIs (including the antibiotic linezolid and methylene blue), drugs that contain tryptophan, or St. John’s Wort.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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