Onset 8mg Tablets

Ondansetron is an anti-sickness medicine. It blocks the action of serotonin, a natural chemical that can trigger nausea and vomiting.

It is used to prevent feeling sick and being sick caused by chemotherapy, radiotherapy or an operation.

Take it exactly as your doctor or pharmacist tells you. The first dose is often taken before your treatment or operation.

• Swallow film-coated tablets with water.
• For melt (orodispersible) tablets, peel back the foil with dry hands, place the tablet on your tongue and let it dissolve, then swallow.
• If you are sick within an hour of taking a dose, ask your doctor or pharmacist whether to take it again.
• If you miss a dose, take it when you remember, unless your next dose is nearly due. Never take two doses together.

Common side effects include:

• headache
• constipation
• a warm or flushed feeling
• tiredness

Get medical help straight away if you have:

• wheezing, swelling of the face, lips or throat, hives or collapse
• chest pain or tightness
• a fast, slow or uneven heartbeat, or fainting
• blurred vision or loss of vision
• agitation, confusion, fever, sweating, shaking or stiff muscles, especially if you take antidepressants
• fits (seizures)

Check with your doctor or pharmacist before taking it if you:

• have heart rhythm problems (including long QT) or heart failure
• have low potassium, sodium or magnesium
• have liver problems
• have a blockage in the bowel or severe constipation
• are having surgery on your tonsils or adenoids
• have phenylketonuria (some melt tablets contain aspartame)
• take other medicines, especially antidepressants or heart medicines

Do not take it with apomorphine (used for Parkinson's disease).

Keep tablets in the original container at room temperature, away from light, heat and moisture. Keep out of the reach of children.

Pregnancy: it should not be used in the first three months of pregnancy, as it slightly raises the chance of cleft lip or palate. If you could become pregnant, use effective contraception and talk to your doctor.

Breastfeeding: do not breastfeed while taking it.