Ondansetron is used to prevent nausea and vomiting associated with cancer chemotherapy or radiation therapy.
Use Ondansetron exactly as directed by your doctor or according to the instructions on the label. Do not use more or less than instructed by your doctor.
Ondansetron suppository is to be inserted into the rectum. Do not eat, chew, or swallow it. Do not use it in any other way. Try to go to the toilet before you insert the suppository.
To use the suppository, follow these steps:
- Wash your hands thoroughly.
- Remove the suppository from the foil wrapper.
- If you are right-handed, lie on your left side and pull your right knee up towards your chest.
- Gently insert the suppository with the pointed end first into your rectum. Gently push the suppository as far as it would go.
- Remain lying in this position for a few minutes to allow the suppository to melt. If you feel that the suppository is slipping out, press your buttocks together. The suppository must remain in the rectum so that the medicine can be absorbed.
The dose of Ondansetron will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on the severity of your condition.
Use the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose to make up for a missed dose.
Alert your doctor if you have a congenital long QT syndrome (an inherited disease causing abnormally fast and erratic heartbeats) as Ondansetron may not be suitable for you.
Do not use this medicine with apomorphine (medicine used to treat Parkinson's disease, a disorder that affects the movement of a person, causing symptoms such as tremors, muscle stiffness, slowed movement and impaired balance or walking).
Inform your doctor if you have the following conditions:
- heart diseases e.g. fast and irregular heartbeat, heart failure (weakness and inability of the heart to pump blood)
- electrolyte imbalance (imbalance of essential minerals in the body) e.g. low potassium or magnesium level in the blood
- blocked bowel
- had previous surgery on the abdomen or tonsils
- liver disease
Let your doctor know if you are pregnant or breastfeeding.
Be sure to check with your doctor or pharmacist before giving Ondansetron to the elderly. Elderly people may be more sensitive to the side effects.
Why is it important to keep my appointments with the doctor?
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
- Routine tests (e.g. potassium or magnesium levels, ECG [test used to record the electrical activity of the heart]) may be done while you are being treated with this medicine. Your doctor will advise you about how often you need to have these tests.
- Regular monitoring for signs and symptoms of allergic reactions, chest tightness or pain, and stomach swelling or pain may also be needed.
Some genetic traits can affect this medicine's efficacy. Individuals who are ultrarapid metaboliser of CYP2D6 may respond poorer to Ondansetron. Although not routinely done, your doctor may advise you to take genetic testing to check if this medicine is best suited for you. If you know you have this gene type, inform your doctor.
Ondansetron may cause any of the following side effects: headache, dizziness, constipation, diarrhoea, flushing, sensation of warmth, hiccups, tiredness, and anxiety.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- signs and symptoms of an allergic reaction e.g. rashes, breathlessness, swelling of the face, eyes or mouth
- signs and symptoms of a heart problem e.g. chest pain, tightness or pressure, difficulty breathing, wheezing
- agitation, confusion, hallucinations (seeing, hearing or feeling things that are not existent), fever, fast heartbeat, excessive sweating, muscle stiffness or spasms
- irregular, fast or abnormal heartbeat, loss of consciousness
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Do not use this medicine with apomorphine (medicine used to treat Parkinson's disease).
Inform your doctor and pharmacist if you are taking any of these medicines:
- medicines to treat depression e.g. mirtazapine, fluoxetine, sertraline, escitalopram, venlafaxine, duloxetine
- medicines for epilepsy (fits or seizures) e.g. carbamazepine, phenytoin
- medicines for cancer e.g. doxorubicin, daunorubicin, trastuzumab
- medicines for irregular heartbeat e.g. amiodarone
- medicines for high blood pressure e.g. atenolol, timolol
- rifampicin (medicine to treat TB, a lung infection known as tuberculosis)
- lithium (medicine for mood disorders)
- ketoconazole (medicine for fungal infection)
- erythromycin (certain antibiotic)
- tramadol (strong painkiller)
This list does not include all medicines that may interact with Ondansetron.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements, and medicines that you buy without a prescription.
Avoid alcohol.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.
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