Ondansetron (By injection)

Ondansetron (on-DAN-se-tron)

Prevents nausea and vomiting.

Brand Name(s):

Amerinet Choice Ondansetron, BD Simplist Ondansetron, Ondansetron Novaplus, PremierPro Rx Ondansetron

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not receive this medicine if you have had an allergic reaction to ondansetron. Do not use this medicine if you are receiving apomorphine (Apokyn®).

How to Use This Medicine:


  • Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot into a muscle or a vein.
  • A nurse or other health provider will give you this medicine.
  • When this medicine is used to prevent nausea and vomiting caused by cancer medicines (chemotherapy), it is usually given 30 minutes before the start of chemotherapy. Additional doses may be given 4 hours and 8 hours after the first dose.
  • When this medicine is used to prevent nausea and vomiting caused by surgery, it is usually given just before anesthesia (medicine to put you to sleep before surgery) or right after surgery if nausea and vomiting begin.
  • Your doctor will give you a few doses of this medicine until your condition improves and then switch you to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor.

Drugs and Foods to Avoid:

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

  • Make sure your doctor knows if you also use carbamazepine (Tegretol®), phenytoin (Dilantin®), rifampin (Rifadin®, Rimactane®), tramadol (Ultram®), or diuretics (water pills, such as furosemide, torsemide, Lasix®).

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding or if you have kidney disease, liver disease, heart disease, heart rhythm problems (such as prolonged QT interval, torsade de pointes), mineral imbalance (such as low potassium or magnesium in the blood), stomach or bowel problems, or a recent stomach surgery. Tell your doctor if you have an allergy to other similar medicines such as alosetron (Lotronex®), dolasetron (Anzemet®), granisetron (Kytril®), or palonosetron (Aloxi®).
  • This medicine can cause changes in heart rhythms, such as QT prolongation. Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat.
  • Check with your doctor right away if you have pain or swelling in your stomach area. These may be signs of a serious stomach or bowel problem.
  • Check with your doctor if severe nausea and vomiting continue after you leave the hospital or cancer treatment center.

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
  • Chest pain, fast, pounding, or uneven heartbeats
  • Lightheadedness, dizziness, fainting

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

  • Constipation, diarrhea
  • Drowsiness, tiredness
  • Fever
  • Headache
  • Pain, itching, burning, swelling, stinging, or a lump under your skin where the needle is placed

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: 11/6/2020

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