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Find out if it's okay to take other medicines while you're taking ondansetron.

Ondansetron is an anti-sickness medicine (sometimes called an antiemetic) that is mainly used in hospitals to help with nausea and vomiting associated with cancer treatments or operations under general anaesthetics.

Here's everything you need to know about taking other medicines with ondansetron, including which it makes less effective and when it might increase the chance of side effects:

It's important to tell your pharmacist if you're already taking any medicines, including herbal medicines and those bought without a prescription, before you start treatment with ondansetron.

Similarly, always check with your pharmacist before taking any new medicines while you're taking ondansetron, to make sure that the combination is safe.

Ondansetron should not be used in combination with apomorphine (used to treat Parkinson's disease).

Ondansetron may reduce the painkilling effect of tramadol.

The following medicines may increase the removal of ondansetron from the body and could therefore make it less effective:

There may be an increased risk of a side effect called the serotonin syndrome if ondansetron is taken with SSRI antidepressants such as citalopram, fluoxetine or paroxetine.

There may be an increased risk of developing an abnormal heart rhythm, seen as a 'prolonged QT interval' on an ECG, if ondansetron is taken with other medicines that can affect the heart, such as the following: