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Aprepitant to prevent sickness


Aprepitant is an anti-sickness medicine. It is taken alongside other medicines to help stop sickness (nausea and vomiting) after chemotherapy.

Take one 125 mg capsule an hour before chemotherapy, and then one 80 mg capsule each morning for the following two days.

The most common side-effects are hiccups, indigestion, constipation and headache.

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About aprepitant

Type of medicine

Neurokinin-receptor antagonist anti-sickness medicine

Used for

Prevention of sickness (nausea and vomiting) associated with chemotherapy

Also called


Available as

Capsules, oral powder sachets

Aprepitant is known as a neurokinin-receptor antagonist. It is prescribed alongside other medicines (dexamethasone and 5HT3-receptor antagonists such as ondansetron) to help stop you from feeling or being sick after chemotherapy. It works by blocking the effect of a naturally produced chemical, called 'substance P'.

Before taking aprepitant

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

  • If you are pregnant or breastfeeding.

  • If you have any problems with the way your liver works.

  • If you have ever had an allergic reaction to a medicine.

  • If you have a rare, inherited blood disorder called porphyria.

  • If you are taking any other medicines, including any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines. Aprepitant interferes with a number of other medicines, including the 'pill' and the 'mini pill'.

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How to take aprepitant

  • Before you start treatment, read the manufacturer's printed information leaflet from inside your pack. The manufacturer's leaflet will give you more information about aprepitant and a full list of side-effects which you may experience from taking it.

  • Take aprepitant capsules exactly as your doctor tells you to. You will be asked to take one 125 mg capsule one hour before your chemo treatment starts, and then one 80 mg capsule each morning for the following two days.

  • Swallow the capsules whole - it may help to take your doses with a drink of water. It is not important whether you take the capsules before or after food.

  • If your child has been prescribed oral powder sachets, the dose will be prepared and given to your child by a doctor or nurse in hospital.

  • If you forget to take a dose, contact your doctor for advice about what to do. Do not take two doses together to make up for a missed one.

Getting the most from your treatment

  • Even if you do not feel like eating or drinking, try to sip water regularly to prevent you from becoming lacking in fluid in the body (dehydrated).

  • Rather than trying to eat three main meals a day, try eating small, simple but nourishing snacks, every few hours.

  • If you are using hormonal contraception (this includes the 'pill' and the 'mini pill'), additional contraceptive precautions such as a condom will be required while you are on aprepitant, and for two months afterwards. If you need further advice about this, speak with your doctor or pharmacist.

  • If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines. This is because many other medicines can interfere with aprepitant and therefore may not be recommended for you.

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Can aprepitant cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with aprepitant. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common aprepitant side-effects - these affect fewer than 1 in 10 people who take this medicine

What can I do if I experience this?


Drink plenty of water and ask a pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know

Feeling tired, sleepy or dizzy

Do not drive and do not use tools or machines if affected


Try to eat a well-balanced diet, and drink several glasses of water each day

Loss of appetite, hiccups, indigestion

If troublesome, speak with your doctor

Changes to some blood tests

Your doctor will check for this

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

How to store aprepitant

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

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.

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.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • Next review due: 27 Dec 2025
  • 28 Dec 2022 | Latest version

    Last updated by

    Michael Stewart, MRPharmS

    Peer reviewed by

    Sid Dajani
  • 22 Oct 2013 | Originally published

    Authored by:

    Helen Allen
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