How does ondansetron work

Stop taking the medication and seek immediate medical attention if any of the following occur:. Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication. Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health.

These factors may affect how you should use this medication. Allergy: People who have had an allergic reaction to dolasetron or granisetron are advised not to take ondansetron. Before you take ondansetron, inform your doctor about any previous adverse reactions you have had to medications.

Contact your doctor at once if you experience signs of an allergic reaction such as skin rash, itching, difficulty breathing, or swelling of the face and throat. Abnormal heart rhythms: Very rarely, ondansetron can affect the heart's electrical activity and cause an irregular heartbeat. This is more likely to happen with the injectable form of ondansetron.

Certain medications e. You are more at risk for this type of abnormal heart rhythm and its complications if you:. If you have heart disease and abnormal heart rhythms, or are taking certain medications e.

Your doctor may monitor your heart rate using a test called an electrocardiogram ECG while you are using this medication. Liver function: Ondansetron is broken down and removed from the body by the liver. Decreased liver function slows down the removal of the medication from the body and increases the risk of side effects from ondansetron.

If you have liver disease or reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Neuroleptic malignant syndrome NMS : Ondansetron, like other similar medications, can cause a potentially fatal syndrome known as neuroleptic malignant syndrome NMS.

If you notice the symptoms of NMS such as high fever, muscle stiffness, confusion or loss of consciousness, sweating, racing or irregular heartbeat, or fainting, get immediate medical attention. Phenylketonuria: People with phenylketonuria lacking the enzyme needed to break down phenylalanine should take forms of ondansetron other than oral dissolving tablets ODT.

The ODT form of ondansetron contains aspartame, an ingredient that cannot be broken down in the body by people who have phenylketonuria. Serotonin syndrome: Severe reactions are possible when ondansetron is combined with other medications that act on serotonin, such as tricyclic antidepressants and serotonin reuptake inhibitors, medications used to treat depression.

These combinations must be avoided. Symptoms of a reaction may include muscle rigidity and spasms, difficulty moving, and changes in mental state including delirium and agitation. Coma and death are possible.

Pregnancy: The safety of ondansetron for use by pregnant women has not been established. This medication should not be used during pregnancy unless the benefits outweigh the risks.

If you become pregnant while taking this medication, contact your doctor immediately. Breast-feeding: It is not known if ondansetron passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. Children: The safety and effectiveness of using this medication to treat nausea and vomiting caused by chemotherapy have not been established for children under 3 years of age.

The safety and effectiveness of using this medication to treat nausea and vomiting caused by radiation or surgery have not been determined for children less than 18 years of age. Its use by this age group is not recommended. Seniors: The safety and effectiveness of using this medication by people 65 years or older to treat nausea and vomiting caused by surgery have not been established. How should this medicine be used?

Other uses for this medicine What special precautions should I follow? What special dietary instructions should I follow? What should I do if I forget a dose? What side effects can this medication cause? What should I know about storage and disposal of this medication? Brand names. Do not chew the film. Other uses for this medicine. What special precautions should I follow? Before taking ondansetron, tell your doctor and pharmacist if you are allergic to ondansetron, alosetron Lotronex , dolasetron Anzemet , granisetron Kytril , palonosetron Aloxi, in Akynzeo , any other medications, or any of the ingredients in ondansetron products.

Ask your pharmacist for a list of the ingredients. Your doctor will probably tell you not to take ondansetron if you are receiving this medication. Be sure to mention any of the following: certain medications for seizures such as carbamazepine Carbatrol, Epitol, Equetro, Tegretol or phenytoin Dilantin ; clarithromycin Biaxin, in Prevpac ; erythromycin E. Your doctor may need to change the doses of your medications or monitor you more carefully for side effects.

Many other medications may also interact with ondansetron, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. If you become pregnant while taking ondansetron, call your doctor. Unless your doctor tells you otherwise, continue your usual diet. Ondansetron may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: headache constipation weakness tiredness chills drowsiness Some side effects can be serious.

If you experience any of the following symptoms, call your doctor immediately or seek emergency medical treatment: blurred vision or vision loss rash hives itching swelling of the eyes, face, lips, tongue, throat, hands, feet, ankles, or lower legs hoarseness difficulty breathing or swallowing chest pain shortness of breath dizziness, light-headedness, or fainting fast, slow or irregular heartbeat agitation hallucinations seeing things or hearing voices that do not exist fever excessive sweating confusion nausea, vomiting, or diarrhea loss of coordination stiff or twitching muscles seizures coma loss of consciousness Ondansetron may cause other side effects.

Call your doctor right away if you have serious side effects. Serious side effects and their symptoms can include the following:. Disclaimer: Our goal is to provide you with the most relevant and current information.

However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare professional who knows your medical history.

Ondansetron orally disintegrating tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well. To help avoid interactions, your doctor should manage all of your medications carefully.

Do not take these drugs with ondansetron. Doing so can cause dangerous effects in your body. Examples of these drugs include:. Taking ondansetron with certain medications raises your risk of side effects from ondansetron.

This is because the amount of ondansetron in your body may be increased. Taking these drugs with ondansetron can make ondansetron less effective. This is because the amount of ondansetron in your body may be decreased. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions.

Always speak with your healthcare professional about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking. Taking it again could be fatal cause death. For people with risk factors for heart arrhythmias: If you have conditions such as heart failure or congenital long QT syndrome, this drug may increase your risk of arrhythmias.

Ask your doctor if you have risk factors for arrhythmias. For people with phenylketonuria: The ondansetron orally disintegrating tablet contains phenylalanine. This amino acid can cause dangerous effects in people with a condition called phenylketonuria.

Research in animals has not shown a risk to the fetus. However, animal studies do not always predict the way humans would respond. This drug should only be used in pregnancy if clearly needed. For women who are breastfeeding: Ondansetron may pass into breast milk and may cause side effects in a child who is breastfed. Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.

For seniors: The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, a higher amount of a drug stays in your body for a longer time. This raises your risk of side effects. For children: This medication has not been studied in children younger than 4 years.

It should not be used in children of this age range. All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:. It has not been confirmed that ondansetron is safe and effective for use in children younger than 4 years.

The kidneys of older adults may not work as well as they used to. Your doctor may start you on a lowered dosage or a different dosing schedule. This can help keep levels of this drug from building up too much in your body. For people with liver disease: If you have severe liver disease, you should not take more than 8 mg of ondansetron per day.