Like all medicines, naproxen can cause side effects, although not everyone gets them.
Common side effects
These common side effects of naproxen happen in more than 1 in 100 people. There are things you can do to help cope with them:
Confusion
If naproxen makes you feel confused, speak to your doctor.
Headache
Make sure you rest and drink plenty of fluids. It's best not to drink too much alcohol. Ask your pharmacist to recommend a painkiller. Headaches should usually go away after the first week of taking naproxen. Talk to your doctor if they last longer than a week or are severe.
Ringing in the ears
If this lasts for more than 1 or 2 days, speak to your doctor as they may need to change your treatment.
Changes in vision
If naproxen causes you to have blurred vision, do not drive, cycle or use tools or machinery until this side effect has worn off. GOV.UK has more information about the law on drugs and driving.
Feeling sleepy or tired
As your body gets used to naproxen, these side effects should wear off.
Feeling dizzy
If naproxen makes you feel dizzy, stop what you're doing and sit or lie down until you feel better. Do not drive, cycle or use tools or machinery until this side effect has worn off. GOV.UK has more information about the law on drugs and driving.
Rashes
It may help to take an antihistamine, which you can buy from a pharmacy. Check with the pharmacist to see what type is suitable for you.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
Call your doctor or call 111 now if you have:
- severe indigestion, heartburn, pains in your stomach, feeling or being sick (nausea or vomiting) or diarrhoea – these can be signs of an ulcer or swelling (inflammation) in your stomach or gut
- vomiting blood or dark particles that look like coffee grounds, blood in your poo, or black poo that looks like tar – these could be signs of bleeding and perforation of your stomach or gut
- a frequent sore throat, nosebleeds and infections – these can be signs of problems with your blood cells, known as agranulocytosis
- feeling faint, tired or short of breath – these can be signs of anaemia
- blood in your pee, passing less pee, feeling or being sick – these can be signs of kidney damage or infection
- a yellow colour to the whites of your eyes or your skin turns yellow, although this may be less obvious on brown or black skin – these can be signs of jaundice or inflammation of the liver
- irregular, slow heartbeats – this can be a sign of high levels of potassium in the blood
- a high temperature, stomach pain and being sick – these can be signs of inflammation of the pancreas
Immediate action required: Call 999 if:
- you have chest pains – this could be a sign of a heart attack and needs to be checked immediately
Immediate action required: Call 999 or go to A&E if:
- you get a high temperature, feel sick or start being sick, get confused, have a headache, neck stiffness and sensitivity to light – these can be signs of aseptic meningitis
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to naproxen.
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.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Long term side effects
Naproxen can cause an ulcer in your stomach or gut if you take it for a long time.
Your doctor may tell you not to take naproxen if you have a stomach ulcer or you have had one in the past. If you need to take naproxen but are at risk of getting a stomach ulcer, your doctor may prescribe another medicine for you to take alongside naproxen to protect your stomach.
The most common symptom of a stomach ulcer is a burning or gnawing pain in the centre of the stomach. But stomach ulcers are not always painful and some people may have other symptoms, such as indigestion, heartburn and feeling sick.
If you're prone to stomach ulcers or have had one before, take paracetamol instead of naproxen as it's gentler on your stomach.
Other side effects
These are not all the side effects of naproxen. For a full list, see the leaflet inside your medicine packet.
Reporting side effects
You can report any suspected side effect using the Yellow Card safety scheme.
Visit the Yellow Card website for more information about reporting side effects.