Ondansetron

What is ondansetron?

Ondansetron is a medicine that is used to treat or prevent nausea (feeling sick, upset stomach) and vomiting (throwing up). Nausea and vomiting may be due to cancer medicines (chemotherapy), radiation treatments, or medicines used for operations (surgery).

Ondansetron may also be used for vertigo or a spinning feeling in children with multiple sclerosis.

You may also hear ondansetron called by its brand name, Zofran. Ondansetron comes as a liquid, a tablet, an orally disintegrating tablet (ODT) and an injection.

Before giving ondansetron to your child:

Tell your doctor if your child is allergic to ondansetron or any ingredient in the formulation.

Talk with your child's doctor or pharmacist if your child has any of the following conditions. Precautions may need to be taken with this medicine if your child has:

• heart problems, including irregular heart rhythms or heartbeats
• liver disease

How should you give your child ondansetron?

Follow these instructions when giving your child ondansetron:

• Give ondansetron by mouth exactly as your doctor or your pharmacist tells you.
• If your child needs ondansetron on an "as needed basis" only, speak to your doctor or pharmacist about when you should give it to your child.
• Your child may take ondansetron with or without food. Give ondansetron with food if it upsets your child's stomach.
• Measure the dose of liquid with the special spoon or syringe that the pharmacist gave you. You may mix the liquid with a small amount of water or milk.
• If your child is taking the ondansetron disintegrating tablet (ODT), place the tablet on top of your child's tongue. It will melt in a few seconds and then your child should swallow.

Ondansetron may be given to your child in a hospital by a nurse from a needle into your child's vein.

What should you do if your child misses a dose of ondansetron?

If your child misses a dose of ondansetron:

• Give it as soon as you remember, if your child is feeling sick.
• Skip the missed dose if it is almost time for the next dose and your child feels well.
• Wait at least 4 hours after ondansetron before you give the next dose, if you gave the dose late. For example, suppose your child's dose times are 8 a.m., 4 p.m. and midnight. If you miss the 8 a.m. dose and remember to give it at 2 p.m. because your child is feeling sick, then wait until 6 p.m. (4 hours) to give the next dose. Then go back to the regular dose time.
• Give your child only one dose at a time. However, if your child vomits (throws up) less than 30 minutes after you gave a dose, you may give another dose.

What are the possible side effects of ondansetron?

Your child may have some side effects while they take ondansetron. Usually your child will not need to see a doctor about them.

These side effects may go away as your child's body gets used to ondansetron. Call your child's contact nurse or doctor if your child has any of these signs or symptoms and they do not go away or they bother your child:

• headache
  
• dizziness
• constipation
• diarrhea (loose, watery stools)
• dry mouth
• feeling of warmth or flushing (red face, body)

Call your child's doctor or nurse as soon as possible, during office hours, if your child has any of these signs:

• rash, hives (raised, red, itchy areas on the skin) or itching

Most of the following side effects are not common, but they may be a sign of a serious problem. Call your child's doctor right away or take your child to the Emergency Department if your child has any of these side effects:

• swelling of eyelids or face
• difficulty breathing
• chest pain, heart pounding or racing (rapid or irregular heart rate), feeling faint

What safety measures should you take when your child is using ondansetron?

There are some medicines that should not be taken together with ondansetron, or in some cases, the dose of ondansetron or the other medicine may need to be adjusted. It is important that you tell your doctor and pharmacist if your child takes any other medications, including:

• antiepileptic medicines, including carbamazepine and phenytoin
• heart medicines, including amiodarone and sotalol
• medicines used to treat mood disorders, including citalopram and sertraline
• antibiotics, such as clarithromycin
• antifungals, such as fluconazole or voriconazole
• cyclosporine, tacrolimus
• cisapride, domperidone

Check with your child's doctor or pharmacist before giving your child any other medicines (prescription, non-prescription, herbal or natural products).

What other important information should you know about ondansetron?

• Other medicines may not work well with ondansetron. Check with your child's doctor or pharmacist before you give your child any other medicines, even medicines that you can buy without a doctor's order (prescription).
• If you do not think that ondansetron is working for your child, talk to your child's doctor.
• You may be asked to give a dose of ondansetron to your child before going to clinic. Give your child ondansetron 30 to 60 minutes before they are given chemotherapy.
• Disintegrating tablets contain aspartame. Children with phenylketonuria (often called PKU) should not receive aspartame.
• Disintegrating tablets contain gelatin. Some diets do not allow gelatin.
• If your child takes ODT:
• Tear the package along the dotted holes (perforations) to make 1 dose.
• Keep the tablet in the package until your child is ready to take ondansetron.
• Peel back the foil.
• Remove the tablet with dry fingers.
• Your pharmacist can show you how to handle ondansetron oral disentegrating tablets.
• If your child is taking part of an ondansetron tablet, a pill splitter will help. You can buy a pill splitter at your pharmacy.
• Keep a list of all medications your child is on and show the list to the doctor or pharmacist.
• Do not share your child's medicine with others. Do not give anyone else's medicine to your child.
• Make sure you always have enough ondansetron on hand in case your child needs it. Call your pharmacy at least 2 days before your child runs out of medicine to order refills.
• Keep ondansetron tablets (regular and ODT) and liquid at room temperature in a cool, dry place away from sunlight. Do NOT store it in the bathroom or kitchen.
• Do not keep any medicines that are out of date. Check with your pharmacist about the best way to throw away outdated or leftover medicines.
  

Keep ondansetron out of your child’s sight and reach and locked up in a safe place. If your child takes too much ondansetron, call your local Poison Information Centre at one of these numbers. These calls are free. 

• Call 1-844 POISON-X, or 1-844-764-7669, from anywhere in Canada except Quebec.
• Call 1-800-463-5060 if you live in Quebec.