Ondansetron Oral and IV (Zofran®)
Pronounce: on-DAN-se-tron
Classification: Antiemetic, Selective 5-HT3 Receptor Antagonist
About Ondansetron Oral and IV (Zofran®)
Ondansetron is a selective 5-HT3 receptor antagonist. 5-HT3 receptors are found in areas of nerves in your brain and stomach that can trigger a vomiting reflex. Ondansetron stops this reflex and can help lessen nausea and vomiting.
How to Take Ondansetron
Ondansetron can be given on as-needed or scheduled basis. It should be taken as prescribed by your provider. How you take your ondansetron and your dosage depends on the cancer treatments you are receiving. If it is being given along with a chemotherapy regimen, it should be given at least 30 minutes before the administration of the chemotherapy. If you are taking ondansetron related to side effects of radiation, you should take the medication 1 to 2 hours before your treatment.
If taking the disintegrating tablet, do not push the tablet through the foil backing. Peel back the foil and gently remove the tablet. Place the tablet on top of your tongue right away to dissolve. After the tablet has dissolved, swallow the saliva in your mouth.
Be sure to tell your healthcare provider about all medications and supplements you take. This medication contains phenylalanine. Tell your provider if you have phenylketonuria (PKU).
This medication, when taken with apomorphine, can cause low blood pressure that can lead to fainting.
Taking this medication with serotonergic medications (often used to treat migraines and depression) can lead to serotonin syndrome. Symptoms of serotonin syndrome that you should tell your provider about include changes in your mental status (agitation, hallucinations, coma), your nervous system (change in heart rate or blood pressure, sweating, dizziness), or in how your muscles are working (tremors, trouble walking). You should call your provider if you are having any symptoms of serotonin syndrome.
High oral (by mouth) doses or intravenous (IV, into a vein) doses can also prolong your QTc, which is related to the electrical activity of your heart. Make sure your providers are aware that you have been prescribed ondansetron before you start any other QTc-prolonging medications, such as chlorpromazine, cisapride, dofetilide, dronedarone, ibutilide, lenvatinib, methadone, quinine, sotalol, vandetanib, vernakalant, ziprasidone, and more. If you have any palpitations or feel like your heart is racing, call your provider right away.
Storage and Handling
All oral (taken by mouth) versions of ondansetron should be stored in the original, labeled container at room temperature. Keep containers out of reach of children and pets.
Where Do I Get This Medication?
Some cancer medications are only available through specialty pharmacies. Your provider or pharmacist will start this process. Your insurance plan may also affect where you can get your medication. Call your prescription plan provider to find out which specialty pharmacies are in-network.
Insurance Information
This medication may be covered by your prescription plan. If you qualify, you may be able to get financial help through patient assistance programs (PAP). Co-pay cards may also be available to lower your out-of-pocket cost if you have commercial (not Medicare/Medicaid/Tricare) insurance. Your pharmacist, social worker, or navigator can help find resources for financial support.
Possible Side Effects of Ondansetron
This medication is given to manage and/or prevent side effects of your cancer treatment. If you are having side effects from this medication, talk to your provider about other options to help manage the side effect this medication is treating. These are some of the most common side effects:
Constipation
Constipation is when you have less bowel movements than usual or are having trouble passing stool. To relieve constipation, you can include fiber in your diet (fruits like prunes, apples, peaches, and pear nectars/juices), drink 8 to 10 glasses of non-alcoholic fluids a day, and stay active. Taking a stool softener once or twice a day can prevent constipation. If you do not have a bowel movement for 2 to 3 days, call your provider.
Headache
Your provider can suggest medications and other ways to help relieve your pain.
Diarrhea
Diarrhea is when you pass three or more stools in a day. Your providers can suggest medications to relieve diarrhea. Do not take any medications to manage your diarrhea without talking to your provider first, as your stool may need to be tested. To manage it, try eating foods that are low in fiber and bland, like white rice and boiled or baked chicken. Try not to eat raw fruits, vegetables, whole grain breads, cereals, and seeds. Soluble fiber is a type of fiber found in some foods that helps absorb (soak up) fluid. Foods high in soluble fiber are applesauce, bananas (ripe), canned fruit, oranges, boiled potatoes, white rice, foods made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Stay hydrated by drinking 8 to 10 glasses of non-alcoholic, non-caffeinated fluid each day.
Fatigue
Fatigue can cause exhaustion, feeling worn out and that your body is "heavy" and hard to move, or being unable to focus. It is common when you have cancer, and it is not the same as feeling tired. You may need to adjust your schedule to manage fatigue. Plan times to rest during the day and save your energy for more important activities. Exercise can help lessen fatigue. Talk to your providers about ways to deal with this side effect.
Dizziness
This medication may cause dizziness. Remember to slowly arise from a seated position or from lying down. If you are experiencing dizziness you should not drive.
Reproductive Concerns
You should talk with your provider before becoming pregnant, getting someone pregnant, or breastfeeding while receiving this medication.
Important but Less Common Side Effects
Allergic Reactions
Some people may have an allergic reaction to this medication. Signs of an allergic reaction are:
- Shortness of breath or trouble breathing.
- Chest pain.
- Rash.
- Itching.
- Flushing (reddening of the skin, often on the face, neck, or chest).
- A drop in blood pressure (you may feel lightheaded, dizzy, or weak).
If you have any of these signs while you are getting an infusion, tell your provider right away. The infusion will be slowed down or stopped. Depending on your reaction, you may still be able to get the medication if you are given medicine to prevent a reaction or if the medication is given at a slower rate.
Heart Problems
This medication can cause slow or abnormal heartbeats or an abnormal heart rhythm called QT prolongation. It can also cause ischemia, which is a slowing or stopping of blood flow to the heart. Tell your care team right away if you feel abnormal heartbeats or if you feel dizzy or faint. If you have pressure or pain in your chest, call 911 or go to the nearest Emergency Room.
Masking of an Ileus or Bowel Obstruction
An ileus is a lack of movement of the bowels. A bowel obstruction is a blockage of the small or large intestine. If it is a complete obstruction, you will have trouble passing gas and stool. A partial blockage can cause diarrhea. Other symptoms can be severe belly pain, nausea, and vomiting. If you are having any of these symptoms, call your provider. Because ondansetron manages nausea and vomiting and these are possible side effects of a bowel obstruction, an ileus or bowel obstruction could be happening and be overlooked.