Ondansetron
Description
Ondansetron is an antiemetic medicine that is used to treat and prevent nausea and vomiting. It is used in the treatment of nausea and vomiting caused by stomach problems, surgery, taking cancer medicines (chemotherapy) or radiation therapy. It works by blocking a natural substance called serotonin in the brain that causes nausea and vomiting.
Ondansetron may cause side effects like constipation, headache, fatigue, diarrhoea, skin rash, pain at the site of injection, etc. Do not use this medicine if you are allergic to it. Consult your doctor if any of these symptoms persist or worsen. The syrup and oral drops forms of ondansetron are recommended for use in children below 4 years of age, tablet forms are not recommended for use in this age group.
Ondansetron is available in many different dosage forms like tablet, injection, syrup, films, oral drops and solution. Your doctor will decide an appropriate dosage form and dose based on your condition. You may have to take this medicine 30 minutes before the start of chemotherapy, 1-2 hours before the start of radiation therapy, or 1 hour before surgery. If you vomit this medicine within one hour of taking it, then you need to repeat the dose.
Ondansetron may not be suitable for all people. Inform your doctor if you have any liver problems, heart failure, electrolyte imbalance, stomach or intestine blockage disorders before taking this medicine. Consult your doctor before using this medicine if you are pregnant, planning a pregnancy or are breastfeeding.
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Side effects
Major & minor side effects for Ondansetron
- Headache
- Constipation
- Fatigue
- Fast or slow or irregular heartbeat
- Chills
- Dry mouth
- Anxiety
- Excessive sweating
- Dizziness
- Skin rash and hives
- Injection site pain
Uses of Ondansetron
What is it prescribed for?
- Chemotherapy induced nausea and vomiting
- Post operative nausea and vomiting
- Radiation induced nausea and vomiting
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Concerns
Commonly asked questions
- Onset of actionOndansetron stops your symptoms immediately. The onset of action for Ondansetron can be observed as follows: Parenteral form (injection) - within 30 minutes Oral form (tablet, syrup, film, tablet SR, suspension) - within 2 hours
- Duration of effectThe effect of Ondansetron lasts for a duration of 12 to 28 hours.
- Safe with alcohol?Interaction with alcohol is unknown. It is advisable to consult your doctor before consumption.
- Is it habit forming?No habit-forming tendencies were reported for Ondansetron.
- Usage in pregnancy?Ondansetron is relatively safe to be used in pregnancy. It is sometimes used to treat nausea and vomiting during the first trimester. However, consult your doctor before taking this medicine.
- Usage while breast-feeding?Ondansetron is not recommended to be used during breastfeeding as it may pass into breast milk and may harm your baby. Consult your doctor before taking this medicine.
Allergy
Do not take Ondansetron if you are allergic to it. Inform your doctor if you have a history of allergy to this medicine. If you notice any symptoms such as a skin rash, itching/swelling anywhere on your body, dizziness, breathing difficulty, etc., seek medical attention immediately.
Apomorphine
Apomorphine is used in the treatment of Parkinson's disease. The combined use of Ondansetron and apomorphine is not recommended due to the risk of lightheadedness, loss of consciousness, and low blood pressure.
Warnings for special population
Pregnancy
Ondansetron is relatively safe to be used in pregnancy. It is sometimes used to treat nausea and vomiting during the first trimester. However, consult your doctor before taking this medicine.
Breast-feeding
Ondansetron is not recommended to be used during breastfeeding as it may pass into breast milk and may harm your baby. Consult your doctor before taking this medicine.
General warnings
Electrolyte imbalances
Ondansetron should be used with caution if you have low levels of potassium or magnesium in the blood as it may cause serious side effects.
Intestinal obstruction
Use Ondansetron with caution if you have a problem of intestinal obstruction caused by colon cancer, Crohn's disease or diverticulitis (swelling in the large intestine) because this medicine can delay the time for food to move through the entire intestine (bowel transit time).
Serotonin syndrome
Serotonin syndrome is a condition where your body produces too much of a chemical called serotonin. This occurs when you take medicines that cause high levels of serotonin in your body. This chemical helps your brain cells and nerve cells to communicate with each other. But too much serotonin causes extreme nerve cell activity and serious symptoms. Caution should be taken when Ondansetron is used along with other same class of medications like granisetron, dolasetron, etc., as it may increase the risk of serotonin syndrome.
Use in children
The tablet form of Ondansetron is not recommended for use in children below 4 years of age as the safety and efficacy data is not available.
Missed Dose
Oral forms: Usually, Ondansetron is taken as a single dose, hence the chances of missing a dose is very low. If you are on a scheduled dosing regimen of this medicine, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose. Do not double the dose to make up for the missed one.
Injection: Since Ondansetron is administered in the hospital setting by a qualified healthcare professional, the chances of missing a dose are low.
Overdose
Oral forms: Never take more than the prescribed dose of Ondansetron. In case you have taken an overdose of this medicine, seek emergency medical attention.
Injection: Since Ondansetron is administered in a clinical setting by a qualified healthcare professional, the chances of an overdose are very low. However, your doctor will take appropriate measures if an overdose is suspected.
All drugs interact differently for person to person. You should check all the possible interactions with your doctor before starting any medicine.
Interaction with Alcohol
Description
Interaction with alcohol is unknown. It is advisable to consult your doctor before consumption.
Instructions
Interaction with alcohol is unknown. It is advisable to consult your doctor before consumption.
Interaction with Medicine
Amitriptyline
Carbamazepine
Phenytoin
Tramadol
Amiodarone
Apomorphine
Disease interactions
QT Prolongation
Ondansetron should be used with caution if you have heart problems and/ or if you are using heart medication as it may cause a heart rhythm problem called prolonged QT intervals (an electrical heartbeat disturbance). It may result in fast, rapid, and irregular heartbeats.
Liver disease
The primary conversion of Ondansetron to its active form happens in the liver. Hence, caution should be maintained if you have liver disease. Please consult your doctor before taking this medicine. Your doctor may suggest liver function tests (LFT) while you are on treatment with Ondansetron.
Food interactions
Information not available.
Lab interactions
Information not available.
Oral forms: Take Ondansetron with or without food as instructed by your doctor. Do not take more than the prescribed medicine.
Avoid eating heavy meals before taking ondansetron. Eat small snacks or light foods and also drink water to avoid dehydration while taking this medicine.
Store this medicine at room temperature away from sunlight. Keep away from the reach of children and pets. Ensure that unused medicine is disposed of properly.
Injection: You should not administer it on your own. Ondansetron injection should be administered by a qualified healthcare professional in a clinical setting.
Your doctor will determine an appropriate dose of this injection based on your clinical condition. Report any undesirable side effects to your doctor promptly.
Tell your doctor about all your current medicines as well as your medical conditions before receiving this medicine.
Miscelleneous
How it works
Ondansetron works by blocking a natural substance called serotonin in the brain that causes nausea and vomiting.
Legal Status
Classification
Category
Antiemetics, 5HT3 receptor antagonists
Schedule
OTC
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CiplaMed. 2021. EMESET Tablets. [online] Available at: < [Accessed 8 January 2021].
Drugs, H., 2021. Ondansetron: Medlineplus Drug Information. [online] Medlineplus.gov. Available at: < [Accessed 8 January 2021].
Medicines.org.uk. 2021. Ondansetron 4 Mg Film-Coated Tablets - Summary Of Product Characteristics (Smpc) - (Emc). [online] Available at: < [Accessed 8 January 2021].
Accessdata.fda.gov. 2021. [online] Available at: < [Accessed 8 January 2021].
Information on this page was last updated on 23 Sep 2021
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