Like all medicines, mometasone can cause side effects but many people have no side effects or only minor ones.
With mometasone nasal spray, if you're not using high doses for a long time, very little medicine is absorbed into the rest of your body, so it's not likely to give you serious side effects.
Common side effects
These common side effects of mometasone nasal spray may happen in more than 1 in 100 people. There are things you can do to help cope with them:
Headaches
Make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller. Talk to your doctor if the headaches are severe.
Unpleasant taste or smell
Rinsing your mouth out with water or brushing your teeth after you use your nasal spray may help.
Sneezing
This will usually settle down as you get used to the medicine.
Nosebleeds, dry or sore nose or throat
If you have nosebleeds, or mometasone is making your nose or throat dry or sore, stop using it for a few days then start again.
Speak to your doctor or a pharmacist if this advice does not help and the side effects still bother you or do not go away.
Serious side effects
Very few people have serious side effects when using mometasone nasal spray.
You're more likely to have a serious side effect if you use high doses of mometasone for more than a few months.
Call a doctor or call 111 straight away if you get:
- eye problems such as pain or blurred vision – these can be signs of increased pressure in your eyes (glaucoma) or a cataract
- problems such as nose pain, sores inside your nose or nosebleeds that do not stop
Serious allergic reaction
In rare cases, mometasone may cause a serious allergic reaction (anaphylaxis).
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Other side effects
These are not all the side effects of mometasone nasal spray. For a full list see the leaflet inside your medicines packet.
You can report any suspected side effect using the Yellow Card safety scheme.