Prescription onlyLower-cost generic available



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Helps you feel less queasy.

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Prescription onlyLower-cost generic available

Our pharmacists’ bottom line

Zofran (Ondansetron) works well to prevent nausea and vomiting, and it's available in different forms that you don't have to swallow.

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  • Available in generic.
  • Available in forms that you don't have to swallow (like a tablet or film that dissolves in your mouth) if you're having trouble keeping anything down.
  • Starts working fast (in 30 minutes.
  • Can cause headaches.
  • Can interact with antidepressants.
  • Can only be used to prevent nausea and vomiting, not to treat if it's already happening.

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Side effects for Zofran (Ondansetron)

From clinical trials of Zofran / Nausea/Vomiting from chemotherapy (0.45 mg/kg)  ( 453)

  • HeadacheHeadache17% for Zofran vs.15% for placebo
  • DiarrheaDiarrhea16% for Zofran vs.18% for placebo
  • ConstipationConstipation11% for Zofran vs.0% for placebo
  • FeverFever8% for Zofran vs.3% for placebo
  • Increased ast and altIncreased ast and alt5% for Zofran vs.0% for placebo
  • RashRash1% for Zofran vs.0% for placebo

Manufacturers don’t say how common these side effects are

  • Abnormally fast heart beat
  • Electrocardiographic alterations
  • Extrapyramidal reactions
  • Grand mal seizure
  • Heart-related chest pain
  • Low blood potassium
  • Low blood pressure

What to expect when you take Zofran (Ondansetron)

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Tips from our pharmacists
  • If you're using the disintegrating tablet, make sure your hands are dry first, peel off the foil and remove the tablet. Place the tablet on the tongue to let it dissolve naturally, then swallow. Don't drink water or anything else.
  • Can cause headache, fatigue or constipation.
  • If you're taking the oral film, don't chew or swallow it. Let it dissolve naturally on the tongue.
  • It takes 30 minutes for Zofran to start working.

Risks and Warnings for Zofran (Ondansetron)

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  • Serotonin syndrome is a rare but potentially life-threatening condition caused when there's too much serotonin active in the brain. Your risk goes up if you use Zofran (Ondansetron) with other medications that affect serotonin (other antidepressants, lithium, medications for migraine headaches, and St. John's wort). Symptoms include fast heart rate, sweating, muscle stiffness or spasms, fever, and confusion. Go to the hospital right away if you have symptoms.

Means that some groups have a high risk of experiencing this side effect

Tips from pharmacists and people taking Zofran (Ondansetron)

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The FDA category for this medication is B. It is advised that you: Probably safe