Ondansetron^®

Ondansetron is a selective 5-HT3 receptor antagonist. By blocking serotonin, it is used to prevent and treat nausea and vomiting.

• Prevention and treatment of nausea and vomiting caused by chemotherapy, radiotherapy, surgery, pregnancy, or dizziness
• Treatment of nausea in acute gastroenteritis

Vial containing 2 mL injectable solution — 2 mg/mL.

Do not use this product if any discoloration, cloudiness, or precipitate is observed.

Ondansetron is compatible for dilution with the following injectable solutions:

• 0.9% sodium chloride
• 5% dextrose in 0.45% sodium chloride
• 5% dextrose in 0.9% sodium chloride
• 5% dextrose
• Ringer’s solution
• Lactated Ringer’s solution

Each vial is for single use only; discard any remaining contents.

Depending on the reason for use, this medicine may be administered by intramuscular injection, intravenous injection over 2 to 5 minutes, or (after dilution) by intravenous infusion over 15 minutes.

• Heart function, especially in older patients and people taking medicines that affect cardiac function
• Electrolyte levels (potassium and magnesium)
• Signs of serotonin syndrome, including high fever, confusion, tremor, and sudden muscle stiffness or spasms
• Reduced bowel function, especially in patients at risk of bowel obstruction

• History of hypersensitivity to Ondansetron, other 5-HT3 antagonists (such as Granisetron or Dolasetron) or any component of the formulation
• Concomitant use with Apomorphine

• If symptoms occur such as increased body temperature, irritability, tremor, muscle stiffness, or flushing, contact your physician immediately.
• Consult your physician if you develop severe constipation.
• This medicine should be used with greater caution in patients with a history of heart disease or irregular heartbeat (arrhythmia).

• Consult your physician before using Ondansetron during pregnancy or breastfeeding.
• The decision to use this medicine during pregnancy or breastfeeding should be made by a physician after weighing its benefits and risks.

Like all medicines, Ondansetron may cause unwanted side effects along with its desired therapeutic effects, although not everyone experiences them. More common possible side effects include:

• Constipation
• Headache and fatigue
• Dizziness
• Hypersensitivity reaction
• Pain and burning at the injection site
• Prolongation of the QT interval on ECG
• Increased liver enzyme levels

Consult your physician or pharmacist about using Ondansetron together with other medicines or supplements.

Each package contains 5 vials.

• Store below 30°C, protected from light and moisture.
• The medicine may be used until the end of the month stated in the expiry date on the package. Do not use or store expired medicines.
• Keep the medicine out of the reach of children.
• Keep the medicine in its original packaging until use.

Ondansetron: Drug information, UpToDate 2025

Medicines.org.uk product information for Ondansetron.