Health Library

Ondansetron (By mouth, into the mouth)

Ondansetron (on-DAN-se-tron)

Prevents nausea and vomiting.

Brand Name(s):

Zofran, Zuplenz

When This Medicine Should Not Be Used:

How to Use This Medicine:

Thin Sheet, Liquid, Tablet, Dissolving Tablet

• Your doctor will tell you how much medicine to use. Do not use more than directed.
• Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
• To use the disintegrating tablet:
  • Do not open the blister pack that contains the tablet until you are ready to take it.
  • Make sure your hands are dry. Peel back the foil, then remove the tablet from the blister pack. Do not push the tablet through the foil.
  • Place the tablet on top of your tongue where it will dissolve in seconds. After the tablet has melted, swallow or take a sip of water.
• To use the soluble film:
  • Make sure your hands are clean and dry.
  • Fold the pouch along the dotted line.
  • While still folded, tear the pouch carefully along the edge. Remove the film from the pouch.
  • Place the film on top of your tongue. It will dissolve in 4 to 20 seconds. Do not chew or swallow the film whole.
  • After the film has dissolved, you may swallow with or without water.
• Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep the soluble film in the foil pouch until you ready to use it.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Do not use this medicine together with apomorphine.
• Some medicines can affect how ondansetron works. Tell your doctor if you are using any of the following:
  • Carbamazepine, fentanyl, methylene blue injection, phenytoin, rifampin, tramadol
  • Diuretics (water pills)
  • MAO inhibitor
  • Medicine used to treat depression (including lithium, mirtazapine, SNRIs, SSRIs)
  • Other medicine for nausea and vomiting

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have liver disease, congestive heart failure, heart rhythm problems (including prolonged QT interval, torsade de pointes), electrolyte imbalance, stomach or bowel problems (including a recent stomach surgery), or phenylketonuria (PKU).
• This medicine may cause the following problems:
  • Heart rhythm problems, including QT prolongation
  • Serotonin syndrome (when used with certain other medicines)
  • Heart problems, including myocardial ischemia (low blood supply to the heart)
  • Stomach or bowel problems
• This medicine may make you dizzy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
• Check with your doctor if severe nausea and vomiting continue after you leave the hospital or cancer treatment center.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Anxiety, restlessness, fever, muscle spasms, twitching, seeing or hearing things that are not there
• Chest pain, trouble breathing, pain or discomfort in the arms, jaw, back or neck, sweating
• Constipation, diarrhea, stomach pain or swelling
• Dark urine or pale stools, nausea, vomiting, loss of appetite, yellow skin or eyes
• Fainting, dizziness, or lightheadedness
• Fast, pounding, or uneven heartbeat

If you notice these less serious side effects, talk with your doctor:

• Headache
• Tiredness or weakness

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024