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Mometasone inhalers - Brand name: Asmanex

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  1. About inhaled mometasone
  2. Key facts
  3. Who can and cannot use mometasone inhalers
  4. How and when to use mometasone
  5. Side effects
  6. How to cope with side effects
  7. Pregnancy and breastfeeding
  8. Cautions with other medicines
  9. Common questions

1. About inhaled mometasone

Mometasone is a medicine used to treat asthma and chronic obstructive pulmonary disease (COPD).

It comes as a "twisthaler" which is a type of inhaler. It's also called a preventer inhaler as it helps prevent you getting symptoms.

Mometasone inhalers are only available on prescription.

Mometasone is a type of medicine known as a corticosteroid (or steroid).

It can also be used to treat other conditions, such as:

2. Key facts

  • Use your mometasone inhaler every day for it to work, even if you do not have any symptoms.
  • You'll usually be given another inhaler called a "reliever" to relieve symptoms when you get them.
  • A mometasone inhaler gets your next dose ready when you twist the cap after using it.
  • Common side effects include a dry or sore throat and oral thrush.
  • It's important to rinse your mouth or brush your teeth after using a steroid preventer inhaler. This is to prevent infections and a sore mouth.
  • You may get a blue steroid treatment card if you need high doses of mometasone to control your symptoms. You may also need to carry a steroid emergency card. Ask your pharmacist or doctor about both of these.

3. Who can and cannot use mometasone inhalers

Adults and children aged 12 years and older can use mometasone.

Mometasone is not suitable for some people. To make sure it's safe for you, tell your doctor if you:

  • have had an allergic reaction to mometasone or any other medicines in the past
  • are pregnant, or trying to get pregnant – your doctor may want to lower your dose
  • have ever had TB (tuberculosis)
  • are taking or have recently taken other steroid medicines
  • are being treated for viral or fungal infections

4. How and when to use mometasone

It's important to use your mometasone inhaler regularly to manage your symptoms. Use it regularly, even if you do not have any symptoms. After using your inhaler, always put the lid back on to keep it clean.

Mometasone inhalers come in 2 strengths that give either 200 micrograms or 400 micrograms of medicine with each "puff". Your doctor or respiratory nurse will tell you which strength is right for you. Always follow their instructions. They may tell you to have 2 puffs at a time from your inhaler. It depends on how bad your breathing is and which inhaler you're using.


The usual dose is 1 or 2 puffs, taken once or twice a day.

If you or your child uses an inhaler once a day, it will work better if it's taken in the evening.

If it's taken twice a day, use it once in the morning and once in the evening.

It’s important to use your mometasone inhaler regularly to manage your condition. Keep using it, even if you do not have any symptoms.

How to use a twisthaler

  1. Remove the cap from your inhaler by twisting it off.
  2. Bring the inhaler up to your mouth, with the mouthpiece pointing toward you.
  3. Gently breathe out, as far as you can.
  4. Put the mouthpiece of the inhaler in your mouth, close your lips tightly around the mouthpiece, and then breathe in rapidly and deeply.
  5. Take the inhaler out of your mouth and hold your breath for around 10 seconds, or for as long as you can. Do not breathe out through the inhaler.
  6. Close the inhaler by replacing the cap as soon as you've used it. Load the dose so it's ready the next time you need to use it. To do this, turn the cap clockwise while gently pressing the cap down until a click sound is heard and the cap is fully closed. The arrow on the cap must be lined up with the window at the bottom on the inhaler.
  7. Rinse your mouth with water or a mouthwash and spit it out – this will help stop you getting oral thrush.

Check your inhaler technique

To get the most from your inhaler, it's important to have your technique checked regularly.

If you're not sure how to use your inhaler, or your technique has not been checked for a year, ask your doctor, nurse or a pharmacist to watch you use it.

It’s very important to use your inhaler properly. This is so you get the right amount of mometasone into your lungs and the most benefit from your medicine.

Will my dose go up or down?

Your dose may go up or down depending on how bad your breathing is. Your doctor will prescribe the lowest dose that controls your symptoms.

If you have agreed on a personal action plan with your doctor or nurse, follow your action plan.

What if I forget to use it?

Use your inhaler as soon as you remember. If it's almost time for your next dose, skip the missed dose and take your next dose as usual.

Do not take a double dose to make up for a forgotten dose.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I use too much?

Using too much mometasone is unlikely to harm you.

If you're worried, talk to your doctor or pharmacist.

Steroid cards

If you are using a steroid inhaler regularly, ask your doctor, nurse or a pharmacist if you need to carry a blue steroid card.


If you need any medical or dental treatment, show your blue steroid card to the doctor, dentist or pharmacist so they know that you're taking mometasone.

5. Side effects

Like all medicines, mometasone can cause side effects, although not everyone gets them.

With inhaled mometasone very little medicine gets into the rest of your body, so it's unlikely to give you side effects.

If you’re on high doses of mometasone, or you’re also taking other steroid medicines or tablets for fungal infections or HIV, you may get underactive adrenal glands as a side effect. Ask your doctor if you need to carry a steroid emergency card.

Common side effects

These common side effects may happen in more than 1 in 100 people.

Keep taking the medicine but talk to your doctor if these side effects bother you or do not go away:

  • dry or sore throat, or hoarse voice
  • oral thrush – a fungal infection that causes white patches, redness and soreness in your mouth
  • headaches

Serious side effects

It's unusual to have any serious side effects when using a mometasone inhaler.

Side effects are more likely to happen if you're on a higher dose of mometasone for a long time (more than a few months).

Tell your doctor straight away if you get:

  • a high temperature, chills, a very sore throat, ear or sinus pain, a cough, coughing up more mucus (phlegm) or a change in colour of your mucus, pain when you pee, mouth sores or a wound that will not heal – these can be signs of an infection
  • "moon face" (a puffy, rounded face), weight gain in the upper back or belly – this happens gradually and can be a sign of Cushing's syndrome
  • a very upset stomach or you're being sick (vomiting), very bad dizziness or passing out, muscle weakness, very tired, mood changes, loss of appetite and weight loss – these can be signs of adrenal gland problems
  • changes in your eyesight, such as blurred vision or a cloudy lens in the eye – these can be signs of increased pressure in your eyes (glaucoma) or a cataract

Serious allergic reaction

It is possible to have a serious allergic reaction (anaphylaxis) to mometasone.

This is different to an asthma attack. If you or your child have asthma symptoms, such as wheezing or have tightness in the chest or throat, use a reliever inhaler. If the symptoms do not improve or get worse, call 999 or go to A&E.

Immediate action required: Call 999 or go to A&E if:

  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

Children and teenagers

Taking mometasone at high doses for a long time can slow down the normal growth of children and teenagers.

Your child's doctor will monitor their height and weight carefully for as long as they're taking this medicine. This will help them spot any slowing down of your child's growth and change their treatment if needed.

Even if your child's growth slows down for a while, it does not seem to have much effect on their eventual adult height.

Talk to your doctor if you're worried. They will be able to explain the benefits and risks of giving your child mometasone.


You can report any suspected side effect to the UK safety scheme.

These are not all the side effects of mometasone. For a full list see the leaflet inside your medicines packet.

6. How to cope with side effects

What to do about:

  • dry or sore throat, or hoarse voice – try rinsing your mouth with water or brushing your teeth after using your inhaler to stop this happening. See your doctor if it does n't improve after 1 week.
  • oral thrush – try rinsing your mouth with water or brushing your teeth after using your inhaler to stop this happening. If you get oral thrush ask a pharmacist to recommend a treatment such as a mouth gel and get them to check that you're using your inhaler correctly. They may suggest that you see your doctor to discuss the best treatment.
  • headaches – make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller and talk to your doctor if the headaches are severe or they last longer than a week.

7. Pregnancy and breastfeeding

Mometasone and pregnancy

It's important to manage your asthma or COPD while you're pregnant. Having uncontrolled breathing can be dangerous for you and your baby.

You can use a mometasone inhaler in pregnancy. There's no evidence that mometasone will harm your baby.

Always tell your doctor if you're pregnant. For safety your doctor will only prescribe mometasone in pregnancy if the benefits outweigh the risks. They will prescribe the lowest dose that works for you.

If you become pregnant while taking mometasone, do not stop using your medicine without talking to your doctor first.

Find more information on using steroid inhalers during pregnancy on the Best Use of Medicines in Pregnancy (BUMPS) website.

Mometasone and breastfeeding

It's generally OK to use your mometasone inhaler while you're breastfeeding.

However, always check with your doctor first. Your baby may need extra monitoring if you use high doses of the inhaler.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

8. Cautions with other medicines

Some medicines and mometasone interfere with each other. This can increase your chance of side effects, or it may mean changing your dose.

Check with a pharmacist or your doctor if you're taking:

  • medicines to treat HIV, such as ritonavir or cobicistat
  • antifungal medicines such as ketoconazole or itraconazole
  • other medicines that contain steroids such as eczema creams, tablets, injections, nasal sprays, eye or nose drops

Mixing mometasone with herbal remedies and supplements

There's very little information about taking herbal remedies and supplements while taking or using mometasone. Ask a pharmacist for advice.


Tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

9. Common questions

How does mometasone work?

Mometasone is a type of medicine called a steroid (also called a corticosteroid).

Steroids closely copy the effects of natural hormones produced in your adrenal glands. The adrenal glands are next to your kidneys.

Mometasone works by calming down your immune system. This reduces the swelling in your lungs that makes it difficult to breathe. It also stops symptoms such as wheezing and coughing developing.

It does not help to treat an asthma attack when you suddenly get coughing, wheezing and breathlessness.

How long does mometasone take to work?

A mometasone inhaler does not start to work straight away.

You'll usually start to wheeze less after using mometasone for 3 to 7 days.

Once your symptoms have improved, you may find you need to use your other inhaler (called a "reliever") less often.

If your shortness of breath or wheezing does not get better after 7 days of using mometasone, or if it gets worse, let your doctor or nurse know as soon as possible.

How long will I use my mometasone inhaler for?

You'll usually use your mometasone inhaler for a long time. It helps prevent your asthma or COPD from getting worse.

It's important you keep using your inhaler even if you feel better.

Is it safe to use mometasone for a long time?

If you use your inhaler as recommended by your doctor, nurse or pharmacist you're unlikely to get any lasting effects.

Inhalers generally deliver a small amount of steroid medicine exactly where you need it. This limits the amount of steroid reaching the rest of your body. It also keeps the risk of side effects as low as possible.

However, for children and teenagers using a high-dose steroid inhaler, their height and weight need to be monitored carefully. This is to make sure the steroid is not affecting their growth. Talk to their doctor if you're worried. They will be able to explain the benefits and risks of giving your child mometasone.

Adults taking high doses have an increased risk of getting adrenal gland problems or weak bones (osteoporosis) over time. This is because more of the steroid gets into your system.

Your doctor will monitor you closely and may prescribe medicines to help strengthen your bones. Calcium-rich foods (such as milk and cheese, or non-dairy milks with added calcium) and regular exercise can also help keep bones healthy.

What will happen if I stop using my mometasone inhaler?

Do not stop using your mometasone inhaler without speaking to your doctor first.

If you have an inhaler to control your asthma or COPD, your breathing problems may return if you suddenly stop using it.

You might feel wheezy or short of breath. Your chest may feel tight and you could start to cough.

Is there anything I need to know about taking mometasone and having surgery?

You do not need to stop mometasone before surgery. Suddenly stopping treatment can make you feel unwell and may give you symptoms.

If you are having surgery or having emergency treatment, for example after an accident, tell the person treating you that you are taking mometasone. Your doctor may decide you need extra steroids for a while.

If you have been given a blue steroid treatment card, show your card to anyone treating you so they can plan your treatment.

How does it compare with other preventer inhalers?

As well as mometasone inhalers, there are other "preventers" that contain steroids such as beclometasone, budesonide, ciclesonide and fluticasone.

They can look very different, and some are for adults only.

It's important to use your own mometasone inhaler. Your inhaler may be different to a friend's or relative's. Their inhaler might contain a different dose of mometasone.

Preventer inhalers are different from the inhalers used during asthma attacks. These are called bronchodilators or "reliever" inhalers.

Do I need a steroid card?

Steroid emergency card (red card)

If you are prescribed steroid medicines such as mometasone, your adrenal glands may not make as much of some of the hormones your body needs such as cortisol (known as the stress hormone). This is known as adrenal insufficiency.

It’s more likely to happen if you take high doses for a long time (especially tablets and injections) or if you regularly use different kinds of steroids at the same time (such as a steroid nasal spray and a steroid inhaler).

Your doctor or pharmacist will assess your risk of adrenal insufficiency based on the type and dose of steroids you’re taking, and may recommend that you carry a steroid emergency card. This card is the size of a credit card and fits in your wallet or purse.

The Addison's Disease Self-Help Group (ADSHG) website has more information about the NHS steroid emergency card.


If you need any medical or dental treatment, or are having surgery or an invasive procedure, show your steroid emergency card to your doctor or dentist. This is important so they know you are having steroid treatment and can give you extra steroids as needed.

Blue steroid card

If you are on a high dose of mometasone, your doctor or pharmacist will also give you a blue steroid treatment card. It tells you how you can reduce the risks of side effects. It also gives details of your doctor, how much mometasone you take and how long the treatment will last for.

If you need any medical or dental treatment, show your blue steroid card to the doctor or dentist.

Can I drink alcohol with it?

Yes, you can drink alcohol with mometasone.

Is there any food or drink I need to avoid?

You can eat and drink normally while using mometasone.

Will it affect my contraception?

Mometasone does not affect any type of contraception, including the combined pill and emergency contraception.

Will it affect my fertility?

There's no clear evidence to suggest that taking mometasone will reduce fertility in either men or women.

However, speak to a pharmacist or your doctor if you're trying to get pregnant.

Can I drive or ride a bike with it?

For most people, using inhaled mometasone will not affect their ability to drive a car or cycle.

However, if your eyesight is affected in any way, do not drive or cycle.

Can I smoke if I use a mometasone inhaler?

Try not to smoke. Smoking irritates the lungs and will make your breathing problem worse.

Mometasone will also work better if you do not smoke.

Speak to your doctor, nurse or pharmacist if you're finding it hard to stop smoking. Stop smoking treatments are available on the NHS.

Can lifestyle changes help with my breathing?

There are several things you can do to help your condition when you're living with asthma. These include:

  • stopping smoking – not smoking can significantly reduce how severe and frequent your symptoms are
  • exercising regularly – exercise is unlikely to trigger your symptoms once you're on appropriate treatment
  • healthy eating – aim for a healthy, balanced diet and lose excess weight if you need to
  • getting vaccinated – it's a good idea to have the annual flu jab and the one-off pneumococcal vaccination

Some people say that using an air filter or air purifier helps with their asthma and COPD symptoms. However, there needs to be more research into this.

Page last reviewed: 5 June 2020
Next review due: 5 June 2023