Compare Zofran vs. Phenergan

Head-to-head comparisons of medication uses, side effects, ratings, and more.

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Zofran (ondansetron)

Prescription only

Phenergan (Promethazine)

Prescription only
Helps prevent nausea and vomiting.

Zofran (ondansetron) works well to prevent nausea and vomiting. It's available in different forms that you don't have to swallow in case you can't keep anything down.

3.6/ 5 average rating with 366 reviewsforZofran
Helps you feel less queasy.

Phenergan (Promethazine) is used to treat and prevent nausea and vomiting from surgery, motion sickness, or pregnancy. While it's cheap and available in different forms to make it easier to take, it can make you feel very sleepy, and its side effects mean that children under 2 and adults over 65 shouldn't take it.

4.4/ 5 average rating with 38 reviewsforPhenergan
Upsides
  • Zofran (ondansetron) comes in many different forms that you don't have to swallow, such as a film that goes on the tongue or a dissolving pill.
  • Zofran (ondansetron) is fast-acting and starts working within 30 minutes.
  • Unlike some other nausea medicines, the side effects for Zofran (ondansetron) are relatively mild.
  • Available in generic.
  • Available as a syrup or tablet that you can take by mouth, or as a rectal suppository if you're unable to take anything by mouth.
Downsides
  • Zofran (ondansetron) doesn't treat nausea and vomiting that's already happening. It only works to prevent future episodes.
  • High doses of Zofran (ondansetron) can cause problems with heart rhythm if you're at risk.
  • If you are also taking antidepressants, you are at higher risk of developing a dangerous condition called serotonin syndrome. Talk with your doctor about your risks.
  • Can make you feel very sleepy, especially if you're taking other drugs that can make you sleepy or if you drink alcohol.
  • Can't be used in children under 2 years of age or if you're over 65 because of increased risk from side effects.
  • Can make your skin more sensitive to the sun.
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Used for
  • Nausea and vomiting due to cancer medicines
  • Prevention of nausea and vomiting due to radiation therapy and after surgery
  • Severe nausea and vomiting in pregnancy
Dosage forms
  • Pill
  • Disintegrating tablet
  • Liquid
  • Sublingual film
  • Pill
  • Liquid
  • Suppository
Price
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Reviews
366 reviews so far
66%
saidit'sworth it
51%
saiditworked well
15%
saidit'sa big hassle

Have you used Zofran (ondansetron)?

Leave a review
38 reviews so far
82%
saidit'sworth it
76%
saiditworked well
5%
saidit'sa big hassle

Have you used Phenergan (Promethazine)?

Leave a review
Side effects
8possible side effects
  • Headache
    9%
  • Oxygen deficiency
    9%
  • Fever
    8%
  • Dizziness
    7%
  • Gynecologic problems
    7%
  • Anxiety
    6%
  • Problems urinating
    5%
  • Itching
    5%
See more detailed side effects
The Phenergan (Promethazine) FDA package insert doesn’t have numbers about how common side effects are.
Risks and risk factors
  • Serotonin syndrome
    • Taking antidepressants, lithium, or some migraine medicines with Zofran (ondansetron).
  • Heart rhythm problems
    • History of long QT syndrome
    • Very high doses of Zofran (ondansetron)
    • Taking other medicines causing heart rhythm problems
    • Low magneium or potassium
    • Heart failure
  • Masking of intestinal blockage and stomach bloating
    • Abdominal surgery
    • Chemotherapy
See more detailed risks and warnings
  • Slowing or stopping of breathing
    • Children under 2 years of age
  • Seizures
    • History of seizures
  • Sunburn
  • Involuntary muscle movements
    • Age over 65
  • Neuroleptic malignant syndrome
See more detailed risks and warnings