COMMON BRAND NAME(S): Zuplenz / Zofran ODT



Description: Ondansetron prevents vomiting due to acute chemotherapy mediated by serotonin

  • Used to
    • Prevent nausea and vomiting caused by chemotherapy and radiation therapy
    • Also used to prevent and treat post-surgery nausea and vomiting by blocking a substance called serotonin that causes vomiting
  • It is a 5-HT3 blocker

How to use ondansetron

  • Always refer to your doctors instructions before taking this medication. Duration and dosage will be determined by your medical condition and its response to the medication. Make sure to take this mediciation in the prescribed amount and time period even after symptoms disappear. Discontinuing the medication before completion of treatment may cause incomplete treatment of condition. If Symptoms persist, consult your doctor.
  • Dissolved on top of tongue and should not be chewed or swallowed; with or without food
  • To prevent nausea from chemotherapy
    • Usually taken within 30 minutes before treatment begins
  • To prevent nausea from radiation treatment
    • Usually taken 1 to 2 hours before the start treatment
  • To prevent nausea after surgery
    • Usually taken 1 hour before the start of surgery

not available

  • Minor side effects (if these symptoms persist or worsen, inform your doctor)
    • Headache
    • Lightheadedness
    • Dizziness
    • Drowsiness
    • Tiredness
    • Constipation
  • Serious side effects (inform your doctor immediately)
    • Stomach pain
    • Muscle spasm/stiffness
    • Vision changes (e.g., temporary loss of vision, blurred vision).
    • Chest pain
    • Slow/fast/irregular heartbeat
    • Severe dizziness
    • Fainting
  • May increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity.
    • Seek immediate medical attention if you develop some of the following symptoms:
      • Fast heartbeat, hallucinations, loss of coordination, severe dizziness, severe nausea/vomiting/diarrhea, twitching muscles, unexplained fever, unusual agitation/restlessness.
  • Severe allergic reactions are rare. Get immediate medical help if you notice the following:
    • Rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.


  • Inform your doctor if you
    • Are allergic to the medication or to other 5-HT3 blockers such as granisetron
    • Have a history of irregular heartbeat, liver disease, stomach/intestinal problems (e.g., recent abdominal surgery, ileus, swelling).
  • May cause QT prolongation, a condition that affects the heart rhythm
    • Risk increases if you have the following conditions”
      • Heart problems, family history of certain heart problems
      • Low levels of potassium or magnesium
        • Usage of such as diuretics/”water pills” or presence of conditions such as severe sweating, diarrhea, or vomiting
      • May cause dizziness and lightheadedness
        • To minimize these effects, get up slowly when rising from a sitting or lying position
  • May contain aspartame
    • Should you have phenylketonuria (PKU) or any other condition that requires aspartame (or phenylalanine) intake restriction, consult your physician.
  • Older adults may be more sensitive to the side effects, especially QT prolongation (see above).
  • During pregnancy, discuss the risks and benefits of use with your doctor.



Taking multiple drugs may affect how medications work and/or cause unwanted side effects. List down all the medications you are taking and inform your physician and pharmacist. Do not take, discontinue, or alter any dose of medications without prior approval of your physician.

  • Should not be used with apomorphine to avoid serious side effects
  • Many drugs besides ondansetron may affect the heart rhythm (QT prolongation)
    • dofetilide, pimozide, procainamide, amiodarone, quinidine, sotalol, macrolide antibiotics (such as erythromycin)
    • Inform your doctor of all medications you are currently taking
  • Risk of serotonin syndrome/toxicity increases if you take other drugs that increase serotonin
    • MDMA/”ecstasy,”
    • John’s wort
    • Certain antidepressants (including SSRIs such as fluoxetine/paroxetine, SNRIs such as duloxetine/venlafaxine),


If overdose is suspected, contact a poison control center or emergency room immediately.


Do not take this medication unless prescribed by your physician

Missed Dose

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and As soon as you remember, take a regular dose or if the time of the next dose is near, wait for it before taking another dose and resume your usual schedule. Do not increase the dose to compensate for the missed dose.


  • Store in the refrigerator or at room temperature between 36-86 degrees F (2-30 degrees C)
  • Do not expose to light and moisture
  • Do not store in the bathroom
  • Keep all medications away from pets and children



Available Brands:

Amnoset 4/Amnoset 8 [ AMN Life Science ]                                                  Emistop [ Claris Lifesciences ]

Emodan [ Korea United Pharma ]                                                                      Kabidan [ Fresenius Kabi ]

Ondafran [ Sandoz ]                                                                                             Onseran [ Yuhan ]

Onzet [ AMN Life Science ]                                                                                                Zofran [ GlaxoSmithKline ]

Also marketed as:

Enset [ Gnana Life Sciences ]                                                                             Nozuca [ Darvys ]

Onset-8 [ Pharmedic Lab ]                                                                                 Onstal-4/Onstal Forte [ Stallion Labs ]

Phil Pharmawealth/Cipla Ondansetron [ Cipla ]                                             Vometron [ PT Pertiwi Agung ]

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