Ondansetron | Side Effects, Dosage, Uses, and More



This drug is used alone or with other medicines to prevent nausea and vomiting due to cancer treatment (chemotherapy) and radiation therapy. It is also used to stop and treat nausea and vomiting after surgery. Ondansetron works by blocking one of the body’s natural substances (serotonin), which causes vomiting.

How To Use Ondansetron ODT

Ondansetron dissolves on the tongue. This is not to chew or swallow like other tablet forms.

Before using Ondansetron, dry your hands. This medicine may come in the bottle or blister pack. If using a blister pack, peel the foil back on the blister pack to remove one tablet. Do not push the bullet through the foil. Immediately after taking the tablet, put it on the tongue. Allow it to completely dissolve, then swallow it with saliva. You do not have to take this product with water. Doing so may increase your chances of getting headache.

To prevent nausea from chemotherapy, take Ondansetron 30 minutes before treatment begins. To prevent nausea with radiation treatment, take this medicine 1 to 2 hours before starting your treatment. To stop nausea after surgery, take Ondansetron 1 hour before starting surgery. This medicine can be taken with or without food. However, your doctor can not tell you to chemotherapy, radiation, or to eat before surgery.

Take any other dose guided by your doctor. Ondansetron can be taken 3 to 3 times a day for 1 to 2 days after your chemotherapy or radiation treatment is over. If you are taking this medicine on time, take advantage of it regularly so that it can get the most benefit. To help you remember, take it every day at the same time.

Dosage is based on your medical condition and medical reaction. Dosage for children can also be based on age and weight. In patients with severe liver problems, the normal maximum dose is 8 mg in 24 hours. Take this medicine exactly as directed. Do not take more medicine or take it more than it has been fixed. Ask your doctor or pharmacist if you have questions.

Inform your doctor if your condition does not improve or if it worsens.

Side Effects

Headache, laziness, dizziness, drowsiness, fatigue or constipation can occur. If these effects persist or become worse, inform your doctor immediately.

Remember that your doctor has prescribed this drug because he or she has decided that your benefit is higher than the risk of side effects. Many people using this drug do not have serious side effects.

Tell your doctor immediately if none of these have potential but serious side effects: stomach ache, muscular spasms / stiffness, change in vision (e.g., temporary loss of vision, blurred vision).

If any of these are rare but very serious side effects, get immediate medical help: chest pain, slow / fast / irregular heartbeat, severe dizziness, unconsciousness

Ondansetron can increase serotonin and rarely cause a very serious condition, which is called serotonin syndrome / toxicity. The risk increases if you are taking other medicines that increase the serotonin, so tell your doctor or pharmacist about all the medicines that you take (see the Drug Interactions section). Get medical help immediately when some of the following symptoms develop: Fast heartbeats, hallucinations, loss of coordination, severe dizziness, severe nausea / vomiting / diarrhea, muscle shaking, unexplained fever, abnormal movement or restlessness

There is no possibility of a very serious allergic reaction to this drug, but stop taking this medicine and if this happens, then seek immediate medical attention. Symptoms of a severe allergic reaction include: Rashes, itching / swelling (especially the face / tongue / throat), severe dizziness, difficulty breathing.

This is not a complete list of possible side effects. If you do not list other effects above, contact your doctor or pharmacist.

In the US – Call your doctor for medical advice about side effects. You can notify the FDA of side effects on 1-800-FDA-1088 or www.fda.gov/medwatch.

In Canada – Call your doctor for medical advice about side effects. You can report the health effects of Canada on 1-866-234-2345.


Before taking ondansetron, tell your doctor or pharmacist whether you are allergic to it; Or other anti-nausea for serotonin blockers (e.g., granisetron); Or if you have any other allergens. This product may contain passive elements, which may cause allergic or other problems. Talk to your pharmacist for more details.

Before using Ondansetron, tell your doctor or pharmacist your medical history, especially: irregular heartbeats, liver disease, stomach / intestinal problems (e.g., abdominal surgery, illusion, swelling).

Ondansetron can cause a condition that affects the heart rhythm (Qt prolonged). Prolonged QT can rarely cause serious (rarely fatal) fast / irregular heartbeat and other symptoms (such as severe dizziness, unconsciousness) that require immediate medical attention.

If you have some medical conditions or QT prolonged other medications are taking Qt can increase the risk of prolonging. Before using Ondansetron, tell your doctor or pharmacist about all the medicines that you take and if you have any of the following conditions: Fixed heart problems (heart failure, slow heartbeats, EKG Qt in the long term), family history of some heart problems (longevity in Qt EKG, sudden cardiac death).

Lower levels of potassium or magnesium in the blood can also increase the risk of QT being long. This risk can increase if you use certain medications (such as diuretic / “water tablets”) or if you have conditions like severe sweating, diarrhea or vomiting. Talk to your doctor about using ondansetron safely.

Ondansetron may make you dizzy or drowsy. Alcohol or marijuana can make you more dizzy or deaf. Unless you can safely do this, do not drive, use machinery, or do anything that requires caution. Avoid alcoholic beverages. If you are using marijuana, talk to your doctor.

To diminish the dizziness and lighthouse, slowly rise while sitting or lying down from the position of lying.

Ondansetron may have aspartame. If you have phenylketonuria (PKU) or any other condition that you need to restrict your intake of aspartame (or phenylalanine), consult your doctor or pharmacist about the safe use of this drug.

Older adults may be more susceptible to the side effects of this drug, especially Qt Latency (see above).

This drug should be used only when it is explicitly required during pregnancy. Discuss the risks and benefits with your doctor.

It is not known whether this medicine passes in breast milk or not. Consult your doctor before breastfeeding.


Your healthcare professional (for example, a doctor or pharmacist) may already be aware of any possible drug interactions and can monitor them for you. Do not start, stop, or change any of the dosages before you check with them first.

Ondansetron should not be used with the following medication as there may be very serious discussions: apomorphine

If you are currently using the medicine listed above, tell your doctor or pharmacist before starting ondansetron.

Before using Ondansetron, use all non-prescription and prescription medicines with your doctor, in particular: tramadol

Ask your doctor or pharmacist for more information.

In addition to other drugs, ondansetron may affect the heart rhythm (QT prolonged) among others, including dofetilide, pimozide, procainamide, amiodarone, quinidine, sotalol, macrolide antibiotics (eg erythromycin). Therefore, before using ondansetron, report all the medicines that you are currently using for your doctor or pharmacist.

If you are taking other medicines that increase serotonin then the risk of serotonin syndrome / toxicity increases. Examples include MDMA / “Bliss,” St. John Plant, some antidepressants (such as fluoxetine / paroxetine such as SSRI, SLRI such as duloxetine (venlafaxine)). The risk of serotonin syndrome / toxicity can be high when you start or increase the dose of these medicines.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medicines with you, and share the list with your doctor and pharmacist.

Over Dose

If someone is treated and has serious symptoms such as difficulty in getting out or breathing, call 911. Otherwise, call the Poison Control Center immediately. American residents can call their local venom control center at 1-800-222-1222. Canadians can call a provincial poison control center.


Do not share this product with others.

Labs and / or medical tests (such as EKGs) should be periodically monitoring your progress or checking side effects. Consult your doctor for more details.

Missed Dose

Try taking each dose at the scheduled time. If you miss a dose, remember it as soon as possible until it is near next dose time. In that case, leave the missed dose and set your normal dose. Do not double the dose to catch up.


Decomposed tablets can be stored between 36-86 ° F (2-30 ° C) at refrigerator or room temperature.

Store away from light and moisture. Do not store in the bathroom. Keep all medicines away from the reach of children and pets.

Until instructed to do so, do not flush the medicines under the toilet or drain them in the drain. When this period expires or does not require it, then properly release this product. Consult your drug vendor or local waste disposal company for more information about relinquishing your product safely.

Disclaimer: DrLinex has made every effort to ensure that all information is factually accurate, comprehensive and up-to-date. However, this article should not be used as a licensed health care professional’s choice of knowledge and expertise. You should always consult your doctor or other health care professional before taking any medication. The information given here is subject to change and it has not been used to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions or adverse effects. The lack of warning or other information for any drug does not indicate that the combination of medicine or medication is safe, effective or appropriate for all patients or all specific uses.

Leave a Reply

Your email address will not be published. Required fields are marked *