Palonosetron to prevent sickness (Aloxi)

Palonosetron is an anti-sickness medicine.

Take one capsule, one hour before your chemotherapy treatment.

The most common side-effect is headache.
Type of medicineAn anti-sickness medicine - a serotonin (5HT3) receptor antagonist
Used forPrevention of sickness associated with chemotherapy in adults
Also calledAloxi®; also Akynzeo® (which contains palonosetron with netupitant)
Available asCapsules and injection

Palonosetron is an anti-sickness medicine. It is known as a serotonin receptor antagonist. It is prescribed to stop you from feeling sick. It works by blocking the effect of a naturally produced chemical in your body, called serotonin. Serotonin is also referred to as 5HT3.

Chemotherapy (or 'chemo' as it is often called) can cause the release of an increased amount of serotonin in your body. There are tiny areas in your small intestine and brain, called 5HT3 receptors. Serotonin acts on these receptors and causes you to feel sick. Palonosetron works by blocking serotonin from acting on the receptors, and this stops you from feeling sick.

There is also a brand of palonosetron which contains another anti-sickness medicine called netupitant - the brand is called Akynzeo®. Netupitant works by blocking the effect of another naturally produced chemical in your body, called substance P.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking palonosetron it is important that your doctor knows:

  • If you are pregnant or breast-feeding. You should not take this medicine if you are expecting, or breast-feeding, a baby.
  • If you have had a problem with severe constipation.
  • If you have been told you have an irregular heartbeat.
  • If you have ever had an allergic reaction to a medicine.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about palonosetron, and it will also provide you with a full list of the side-effects which you could experience from taking it.
  • Take the capsule exactly as your doctor tells you to. You will be asked to take a single dose of one capsule (containing 500 micrograms of palonosetron), one hour before your chemo treatment starts.
  • Swallow the capsule whole - it may help to take it with a drink of water. You can take the capsule either with or without food.
  • You will only be given palonosetron before you have chemotherapy. If you need anything for sickness after your treatment, you will be given a different medicine to take.
  • Even if you do not feel like eating or drinking, try to sip water regularly to prevent you from becoming lacking in fluids (dehydrated). Also, rather than trying to eat three main meals a day, try eating small, simple but nourishing snacks, every few hours.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the more common ones associated with palonosetron. The best place to find a full list of the side-effects which can be associated with your medicine, is from the manufacturer's printed information leaflet supplied with the medicine. Alternatively, you can find an example of a manufacturer's information leaflet in the reference section below. Speak with your doctor or pharmacist if any of the following become troublesome.

Common palonosetron side-effects (these affect less than 1 in 10 people)
What can I do if I experience this?
HeadacheDrink plenty of water and ask your doctor to prescribe/recommend a suitable painkiller
ConstipationTry to eat a well-balanced diet, and drink several glasses of water each day. Let your doctor know if this continues
DiarrhoeaDrink plenty of water to replace lost fluids. Let your doctor know if this continues
Feeling dizzy or tiredDo not drive and do not use tools or machines while affected

Important: in a very few people, medicines like palonosetron can cause a problem called serotonin syndrome. Although this occurs only rarely, should you develop stiff or shaky muscles, a very high temperature (fever), a fast heartbeat, or become confused or agitated, you should call for medical assistance straightaway.

If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

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Further reading & references

Current Version:
Helen Allen
Peer Reviewer:
Prof Cathy Jackson
Document ID:
28714 (v2)
Last Checked:
30 December 2016
Next Review:
30 December 2019
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The information on this page is written and peer reviewed by qualified clinicians.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.