Mometasone furoate inhaler for asthma prevention (prophylaxis)

This leaflet is for parents and carers about how to use this medicine in children. Our information may differ from that provided by the manufacturers, because their information usually relates to adults. Read this leaflet carefully. Keep it somewhere safe so that you can read it again.

mometasone twisthalers should not be used during an acute asthma attack (sudden onset of wheezing and breathlessness). Use your child’s reliever medicine (usually in a blue inhaler).

Name of medicine

Mometasone furoate (known as mometasone for short)

Brand name: Asmanex®; contains a small amount of lactose

This leaflet is about the use of inhaled mometasone furoate (twisthaler) for asthma. It is taken regularly in order to prevent attacks. (This is sometimes called asthma prophylaxis.)

Why is it important for my child to take mometasone?

Mometasone is a steroid medicine. It reduces inflammation in the lungs that can act as a trigger for an asthma attack, and so should reduce the number of attacks. Mometasone is commonly called a ‘preventer’ medicine. It is important that your child takes it regularly to help prevent asthma attacks.

mometasone will not reduce wheezing or breathlessness during an acute asthma attack – your child should use their ‘reliever’ inhaler for this (this is often a blue salbutamol inhaler).

What is mometasone available as?

Mometasone has to be inhaled into the lungs (breathed in). A special device called a twisthaler is used and consists of a plastic device containing dry powdered medicine. This is used in older children aged 12–18 years.

Different sizes are available, which give 200 or 400 micrograms of mometasone per metered inhalation (puff).

When should I give mometasone

Mometasone may be given once or twice each day. Your doctor will tell you how often to give it.

Once a day: this is usually in the evening.

Twice a day: this should be once in the morning and once in the evening. Ideally, these times are 10–12 hours apart, for example some time between 7 and 8 am, and between 7 and 8 pm.

Give the medicine at about the same time(s) each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of mometasone (the dose) that is right for your child. The dose will be shown on the medicine label.

Your doctor may suggest that your child has a low dose to start with. They may then increase the dose (by increasing the number of puffs you give, or using an inhaler that gives a higher dose) as your child gets used to the medicine and depending on how your child responds to it.

It is important that you follow your doctor’s instructions about how much to give.

How should I give mometasone?


  • Hold the twisthaler straight up with the pink portion on the bottom. This is important to make sure you get the right amount of medicine.
  • Remove the cap from the twisthaler by twisting it off.
  • As you lift off the cap the dose counter on the pink portion will count down by one. This action gets the medicine ready for you to inhale.
  • Ask your child to breathe out normally, as far as they can. Place the mouthpiece of the twisthaler firmly between the lips, ensuring a good seal around the mouthpiece.
  • Your child should breathe in rapidly and deeply so that they inhale all the medicine.
  • Take the twisthaler out of your child’s mouth. They should close their mouth and hold their breath for 5–10 seconds, or for as long as they can comfortably manage. They can then breathe normally. It is important not to rush this step.
  • Close the twisthaler by twisting on the cap. Follow the instructions that come with your twisthalers regarding storage when not in use.
  • If your child has to take more than one puff, they should breathe normally for a minute or so before giving the next one.
  • Your child should rinse their mouth out thoroughly with water or clean their teeth.

Your doctor or asthma nurse will show you how to use the twisthaler. If you are not sure whether you are using the twisthaler properly, or need help, contact your asthma nurse or pharmacist, who will be able to show you or check what you are doing.

An instruction leaflet will also be provided with the twisthaler. Follow the instructions that come with your twisthaler for how to get it ready. If you are not sure how to do this, ask your pharmacist or nurse to show you.

When should the medicine start working?

Mometasone needs to be given regularly to prevent asthma and wheeze. It will start to work within 24 hours, but it may take a few weeks to reduce the inflammation. Your child may continue to have attacks during this time, but they should start to happen less often. Continue to give the medicine as told by your doctor or nurse, even if your child does not have any wheeze or symptoms of asthma.

If your child’s asthma does not seem to be getting any better, and they still need to use their reliever medicine often, contact your doctor or asthma nurse.

What if my child is sick (vomits)?

If your child is sick at any time, you do not need to give them another dose, as the inhaled medicine will still work.

What if I forget to give it?

If you usually give it once a day in the evening

If you remember before bedtime, give the missed dose. You do not need to wake up a sleeping child to give a missed dose. You can give the missed dose in the morning, as long as this is at least 12 hours before the evening dose is due.

If you usually give it twice a day

If you remember up to 4 hours after you should have given a dose, give your child the missed dose. For example, if you usually give a dose at about 7 am, you can give the missed dose at any time up to 11 am. If you remember after that time, do not give the missed dose. Just give the next dose as usual.

Never give a double dose of mometasone, unless your doctor has told you to.

What if I give too much?

You are unlikely to do harm if you give an extra dose of mometasone by mistake. If you are concerned that you may have given too much, contact your doctor or or local NHS services (111 in England and Scotland; 111 or 0845 4647 in parts of Wales).

Have the medicine or packaging with you if you telephone for advice.

Are there any possible side effects?

We use medicines to make our children better, but sometimes they have other effects that we don’t want (side effects).

Side effects you must do something about

If your child is short of breath or is wheezing, or their face, lips or tongue start to swell, or they develop a rash, they may be allergic to mometasone. Take your child to hospital or phone for an ambulance straight away.

If your child is taking a high dose of mometasone, they may develop a yeast infection in the mouth, called oral thrush. If you notice a thick white or cream-coloured covering on your child’s tongue, or the mouth is red and irritated, contact your doctor for advice, as this may need treatment. You can help prevent this by making sure that your child rinses their mouth with water after using mometasone.

Other side-effects you need to know about

  • If your child’s voice is hoarse or their throat is sore after using the twisthaler, encourage them to rinse out their mouth after every use.

  • Your child may have a dry mouth. Eating citrus fruits (e.g. oranges) and sipping water may help.

  • The mometasone may slow the speed at which your child grows at the start of treatment, but they will probably catch up when their asthma is properly controlled. Their final adult height should not be affected. Your doctor should monitor the growth of your child while they are receiving treatment with mometasone.

  • All steroid medicines, including mometasone, but only in high doses, may affect the adrenal glands so that they produce less of a hormone called cortisol when the body is stressed (e.g. during illness or injury). This means that your child may have more difficulty fighting off an infection, or may recover less quickly from injury or after surgery.

There may sometimes be other side effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side effects to a UK safety scheme at

Can other medicines be given at the same time as mometasone?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • The mometasone should not be taken with some common drugs that you get on prescription. It is important to tell your doctor and pharmacist that your child is taking mometasone.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal and complementary medicines.

Is there anything else I need to know about this medicine?

If your child becomes very unwell or requires an operation, tell the doctors that your child uses a mometasone twisthaler.

In a very few cases, children become unwell when they stop or reduce the amount of any steroid medicine they are taking, including mometasone (in high doses). This may include your child becoming very tired or dizzy, having stomach pains or vomiting. If you are at all worried about this, contact your doctor straight away.

If your child is unwell, do not change the dose (number of puffs).

General advice about medicines

  • Try to give medicines at about the same times each day, to help you remember.
  • If you are not sure a medicine is working, contact your doctor but continue to give the medicine as usual in the meantime. Do not give extra doses, as you may do harm.
  • Only give this medicine to your child. Never give it to anyone else, even if their condition appears to be the same, as this could do harm.
  • If you think someone else may have taken the medicine by accident, contact your doctor for advice.
  • Make sure that you always have enough medicine. Order a new prescription at least 2 weeks before you will run out.
  • Make sure that the medicines you have at home have not reached the ‘best before’ or ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

Where should I keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight.
  • It does not need to be kept in the fridge.
  • Make sure that children cannot see or reach the medicine.
  • Keep the medicine in the container it came in.

Who to contact for more information?

Your child’s doctor, pharmacist or nurse will be able to give you more information about mometasone and about other medicines used to treat asthma and wheeze.

England: NHS 111

Tel 111

Scotland: NHS 24

Northern Ireland: NI Direct

Wales: NHS Direct

Tel 111 (free) or 0845 46 47 (2p per minute)

Asthma UK

0300 222 5800

Copyright disclaimer

Version [1]. © NPPG, RCPCH and WellChild, all rights reserved. Review by July 2016.

The primary source for the information in this leaflet is the British National Formulary for Children. For details on any other sources used for this leaflet, please contact us through our website,

We take great care to make sure that the information in this leaflet is correct and up-to-date. However, medicines can be used in different ways for different patients. It is important that you ask the advice of your doctor or pharmacist if you are not sure about something. This leaflet is about the use of these medicines in the UK, and may not apply to other countries. The Royal College of Paediatrics and Child Health (RCPCH), the Neonatal and Paediatric Pharmacists Group (NPPG), WellChild and the contributors and editors cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this leaflet.