Naproxen Side Effects: What to Expect and When to Seek Help
From stomach problems to heart and kidney risks, discover what naproxen side effects to watch for and when to seek medical advice.
Key takeaways
Naproxen is an NSAID used to relieve pain and inflammation.
The most common side effects are indigestion, stomach pain, nausea, headache and dizziness.
Serious risks include stomach ulcers and bleeding, kidney problems, and heart attack or stroke.
These risks are higher at higher doses, with long-term use or in people aged 65 and over.
Taking naproxen with or just after food may help reduce stomach discomfort.
Seek urgent medical help for black stools, vomiting blood, chest pain or difficulty breathing.
Naproxen is commonly prescribed to relieve pain and reduce inflammation associated with conditions such as arthritis, gout and muscle or joint injuries. Although it can help manage these symptoms, it may also cause side effects, ranging from mild digestive discomfort to more serious complications affecting the stomach, kidneys and cardiovascular system.
Most people will not experience every side effect, and some may not experience any. However, understanding what naproxen can cause, why certain reactions happen and when to seek medical advice can help you use it more safely.
This guide explains the common and serious side effects of naproxen, its potential long-term risks, important medicine interactions and practical steps to reduce complications.
What is naproxen and how does it work?
Naproxen is a non-steroidal anti-inflammatory drug (NSAID), a group of medicines that also includes ibuprofen. It works by reducing the production of substances called prostaglandins, which contribute to pain, inflammation and swelling.
It is prescribed for several conditions, including:
Osteoarthritis and rheumatoid arthritis
Ankylosing spondylitis
Gout
Period pain
Muscle and joint injuries
Naproxen is available in different strengths and formulations, including standard and gastro-resistant tablets. These formulations differ in how the medicine is released, but they contain the same active ingredient and can cause similar systemic side effects.
For further information, see the NHS guide to naproxen.
What are the common side effects of naproxen?
Common side effects of naproxen mainly involve the digestive system, although some people experience headaches, dizziness or skin reactions. Not everyone taking naproxen will experience these effects.
Recognised side effects include:
Digestive problems: Indigestion, stomach pain, bloating, nausea, vomiting, constipation, diarrhoea or wind.
Headaches: Some people experience headaches while taking naproxen.
Dizziness or drowsiness: You may feel dizzy, sleepy or tired.
Tinnitus: Ringing or other noises in the ears.
Skin reactions: A rash may develop.
These effects are not necessarily a sign of a serious complication. However, speak to your pharmacist or prescriber if they persist, become worse or interfere with your daily activities.
Taking naproxen with or just after food may help reduce stomach discomfort. If you experience dizziness, drowsiness or vision problems, avoid driving or operating machinery until you feel well enough.
You can check the NHS list of naproxen side effects and the patient information leaflet supplied with your specific medicine.
Can naproxen cause stomach problems?
Yes. Naproxen can cause indigestion, stomach pain and, in some cases, more serious complications such as stomach ulcers and gastrointestinal bleeding.
Prostaglandins help protect the stomach lining by supporting the production of mucus and other protective substances. Because naproxen reduces prostaglandin production, it can weaken some of these protective mechanisms, making the digestive tract more vulnerable to damage.
The effects can range from:
Indigestion and heartburn
Nausea and stomach discomfort
Stomach or intestinal ulcers
Gastrointestinal bleeding
Perforation of the digestive tract in serious cases
The risk of ulcers and bleeding is higher in people taking larger doses or using naproxen for longer periods. It is also increased in older adults, people with a previous history of stomach ulcers and those taking certain medicines, such as anticoagulants or corticosteroids.
Your prescriber may recommend the lowest effective dose for the shortest necessary period. Depending on your individual risk, they may also prescribe a proton pump inhibitor (PPI), such as omeprazole, to help reduce the risk of stomach ulcers.
For people with osteoarthritis who need an oral NSAID, NICE recommends considering gastrointestinal, kidney, liver and cardiovascular risks and offering gastroprotection.
If you have previously had a stomach ulcer or gastrointestinal bleeding, tell your prescriber before taking naproxen. They may consider stomach protection or an alternative pain relief option, depending on your medical history.
Which naproxen side effects are serious?
Although many side effects are mild, naproxen can occasionally cause serious reactions that need prompt medical attention.
Look out for the following warning signs:
Possible complication | Symptoms to watch for |
|---|---|
Stomach ulcer or bleeding | Black, sticky stools, vomiting blood or material resembling coffee grounds, severe stomach pain or unusual paleness |
Kidney problems | Passing less urine than usual, blood in the urine or unexplained swelling in the ankles, feet or hands |
Severe allergic reaction | Swelling of the face, lips, tongue or throat, a raised itchy rash or difficulty breathing |
Heart or circulation problems | Chest pain, sudden weakness on one side of the body or difficulty speaking |
Heart failure or fluid retention | Breathlessness, unusual tiredness or swelling in the legs and ankles |
Serious skin reaction | A severe rash, blistering or peeling skin |
What should you do if you get serious side effects from naproxen?
If you notice black, tarry stools or vomit blood, stop taking naproxen and seek urgent medical attention. These may be signs of gastrointestinal bleeding.
If you develop symptoms suggesting serious kidney problems or another serious side effect, seek urgent medical advice through NHS 111 or your healthcare professional.
Call 999 if you experience severe breathing difficulty, suspected heart attack, stroke or another life-threatening emergency.
Do not dismiss these symptoms simply because you have only been taking naproxen for a short time. Serious gastrointestinal complications can occur at any stage of treatment.
The NHS naproxen guidance provides further information about symptoms that need medical attention.
What are the long-term risks of taking naproxen?
Long-term naproxen use can increase the risk of stomach ulcers and bleeding, kidney problems, heart attack and stroke, raised blood pressure and anaemia. Taking naproxen regularly, particularly at higher doses or for extended periods, can increase the risk of certain complications. The likelihood depends on factors such as your dose, duration of treatment, age, medical history and other medicines you take.
Potential risks include:
1. Stomach ulcers and gastrointestinal bleeding
Prolonged use can increase the risk of ulcers, bleeding and, in rare cases, perforation of the stomach or intestines. These complications can sometimes occur without obvious warning symptoms.
2. Kidney problems
Naproxen can reduce blood flow to the kidneys by interfering with prostaglandin production. This may affect kidney function, particularly in people with existing kidney disease, dehydration, heart failure or certain other medical conditions.
3. Cardiovascular complications
NSAIDs can be associated with an increased risk of cardiovascular events, including heart attack and stroke. The risk may be greater with higher doses and prolonged treatment. Although some evidence suggests naproxen may have a lower risk of arterial blood clots than certain other NSAIDs, a cardiovascular risk cannot be ruled out.
4. Raised blood pressure and fluid retention
Naproxen may cause fluid retention and swelling. It can also worsen existing high blood pressure or heart failure in susceptible people.
5. Anaemia
Long-term or repeated gastrointestinal bleeding can lead to anaemia. Possible symptoms include tiredness, weakness, breathlessness and looking paler than usual.
6. Reduced female fertility
Like other medicines that inhibit prostaglandin production, naproxen may temporarily interfere with ovulation and make it more difficult for some women to conceive while taking it. It is not recommended for women trying to become pregnant.
These risks do not mean that everyone taking naproxen regularly will develop complications. However, if you need ongoing treatment, your prescriber should review it periodically and consider whether the benefits continue to outweigh the risks.
If you are prescribed naproxen for an extended period, ask your healthcare professional whether you need periodic blood pressure checks or blood tests to monitor your kidney function and overall health.
The eMC Summary of Product Characteristics for naproxen provides further information about its warnings, precautions and adverse effects. Always check the product information for your specific medicine.
Who is more likely to experience naproxen side effects?
Side effects are more likely in people aged 65 or over and in those with stomach, heart or kidney problems, or who take certain other medicines.
Tell your prescriber or pharmacist before taking naproxen if you:
Are aged 65 or over.
Have or have previously had a stomach ulcer or gastrointestinal bleeding.
Have heart disease, high blood pressure or a history of stroke.
Have kidney or liver problems.
Have asthma or have previously reacted to aspirin, ibuprofen or another NSAID.
Have Crohn's disease or ulcerative colitis.
Have a blood-clotting disorder.
Take anticoagulants, corticosteroids or certain antidepressants.
Naproxen also requires particular care during pregnancy and breastfeeding.
Pregnancy: Avoid taking naproxen during pregnancy unless a healthcare professional specifically advises you to. NSAIDs may affect fetal development. From 20 weeks of pregnancy, prolonged use may cause problems such as reduced amniotic fluid due to effects on fetal kidney function. Systemic NSAIDs are contraindicated during the third trimester, from 28 weeks onwards.
Breastfeeding: Naproxen passes into breast milk in small amounts and is not usually recommended while breastfeeding. Other medicines, such as ibuprofen, may be more suitable, but you should discuss the options with a healthcare professional.
If you are pregnant, planning a pregnancy or breastfeeding, speak to your doctor or pharmacist before taking naproxen.
Check with a healthcare professional before taking naproxen if you have any of these risk factors. You may need closer monitoring, stomach protection or an alternative medicine to reduce the risk of complications. Do not start naproxen without discussing your medical history and current medicines with your prescriber or pharmacist.
Further information is available from the NHS pregnancy and breastfeeding advice and the MHRA guidance on NSAID use after 20 weeks of pregnancy.
How can you reduce the risk of naproxen side effects?
You cannot eliminate every possible side effect, but following your prescriber's instructions and taking a few precautions can help reduce the risk of complications.
Take it with or just after food: This may help reduce stomach discomfort.
Follow the prescribed dose: Use the lowest effective dose for the shortest period recommended by your prescriber.
Avoid combining NSAIDs: Do not take naproxen alongside ibuprofen or other NSAIDs unless a healthcare professional specifically advises you to.
Limit alcohol: Alcohol can increase the risk of stomach irritation, ulcers and gastrointestinal bleeding.
Maintain adequate fluid intake: Dehydration can increase the risk of kidney problems, particularly during illness.
Discuss stomach protection: Ask your prescriber whether a medicine such as omeprazole is appropriate if you have an increased risk of gastrointestinal complications.
Take gastro-resistant tablets correctly: Swallow them whole with water. Do not crush or chew them.
Report suspected side effects: You can report suspected adverse reactions through the MHRA Yellow Card Scheme.
Do gastro-resistant naproxen tablets protect your stomach?
Gastro-resistant tablets have a coating that delays the release of naproxen until the tablet reaches the intestine. This changes where the medicine is released, but it does not remove the risk of stomach ulcers, gastrointestinal bleeding or other complications associated with NSAIDs.
This is because naproxen can affect the protective prostaglandins involved in maintaining the digestive tract, not simply irritate the stomach through direct contact.
Gastro-resistant tablets should therefore not be considered a guarantee against stomach-related side effects. Follow the instructions supplied with your specific medicine.
Do not crush or chew gastro-resistant naproxen tablets. Their special coating is designed to delay the release of the medicine until it reaches the intestine. Swallow them whole with water and follow the instructions supplied with your specific medicine.
Which medicines can interact with naproxen?
Naproxen can interact with several medicines. Some combinations increase the risk of side effects, while others may affect how well your medicines work.
Important interactions include:
Anticoagulants: Medicines such as warfarin can increase the risk of bleeding when taken with naproxen.
Aspirin and antiplatelet medicines: These can increase the risk of gastrointestinal bleeding. If you have been prescribed low-dose aspirin, do not stop taking it without medical advice; ask your prescriber how to manage the combination.
Corticosteroids: Medicines such as prednisolone can increase the risk of stomach ulcers and bleeding.
Antidepressants: Some antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), can increase the risk of bleeding when combined with NSAIDs.
Blood pressure medicines: ACE inhibitors and angiotensin receptor blockers (ARBs) may be less effective, and the combination can increase the risk of kidney problems in susceptible people.
Diuretics: Also known as water tablets, these can contribute to kidney problems when combined with NSAIDs.
Methotrexate and lithium: Naproxen may affect how these medicines are eliminated from the body, potentially increasing their levels.
Digoxin: Naproxen may increase digoxin levels in some people.
Always tell your doctor or pharmacist about all the medicines you take, including over-the-counter painkillers, supplements and herbal products.
For further information, see the NHS guidance on naproxen interactions and the interactions section of your specific medicine's eMC product information.
Buy Pain Treatments Safely and Securely
Discover a range of Pain Relief Treatments to help relieve common aches and pains, from headaches to muscular discomfort. PillPharm's GPhC-registered UK pharmacy team ensures prescribed medication is dispensed appropriately and delivered discreetly in plain, tracked packaging.
Includes free delivery & prescription
When should you seek medical advice about naproxen?
Speak to your pharmacist or doctor if side effects persist, worsen or interfere with daily activities. Seek urgent medical advice if you notice signs of gastrointestinal bleeding, kidney problems or another serious reaction. Call 999 for life-threatening symptoms, including suspected heart attack, stroke or severe breathing difficulty.
If your pain is not improving or keeps returning, arrange a review to discuss your treatment.
Looking for pain relief advice? Explore PillPharm's Pain category for information about available options and pharmacy support.
Frequently Asked Questions
The common side effects are similar across naproxen strengths and include indigestion, stomach pain, nausea, headache, dizziness, drowsiness, constipation, diarrhoea, bloating, tinnitus and skin rash. The likelihood of side effects can depend on the dose and individual risk factors. Taking naproxen with or just after food may help reduce stomach discomfort.
Yes. Naproxen reduces prostaglandins that help protect the stomach lining, which can increase the risk of ulcers and gastrointestinal bleeding. The risk is higher with prolonged use, higher doses, older age or a previous history of ulcers. Your prescriber may recommend a stomach-protective medicine, such as omeprazole, depending on your individual risk.
Regular or prolonged use can increase the risk of stomach ulcers and bleeding, kidney problems, fluid retention, raised blood pressure and cardiovascular complications. Naproxen may also affect female fertility. The likelihood of these effects depends on your dose, duration of treatment and medical history. If you need to take it regularly, arrange periodic reviews with your prescriber.
Naproxen can increase the risk of heart attack and stroke, particularly at higher doses or with long-term use. Some evidence suggests this risk may be lower than with certain other NSAIDs, but it isn’t absent. If you have heart disease, high blood pressure, heart failure or a previous stroke, speak to your doctor before taking it.
Yes. Naproxen can reduce blood flow to the kidneys and affect their function. The risk is higher in people with existing kidney problems, dehydration, heart failure or those taking certain blood pressure medicines and diuretics. Passing less urine, blood in the urine or unexplained swelling may indicate a problem and needs medical assessment.
Black, sticky or tar-like stools can be a sign of bleeding in the stomach or intestines. This is a potentially serious side effect of naproxen. Stop taking it and seek urgent medical attention. Do not wait to see whether the symptom settles.
It is best to limit alcohol while taking naproxen. Drinking alcohol can increase the risk of stomach irritation, ulcers and gastrointestinal bleeding. If you are unsure how alcohol may affect you while taking your prescribed dose, ask your pharmacist or doctor.
Naproxen can be prescribed to older adults when appropriate, but people aged 65 and over may have a greater risk of complications, particularly gastrointestinal bleeding and kidney problems. A prescriber may consider a lower dose, stomach protection and closer monitoring depending on the person’s health and other medicines.
If you forget a dose, take it when you remember unless it is nearly time for your next dose. If your next dose is due soon, skip the missed dose and continue with your usual schedule. Do not take a double dose to make up for one you missed. Always follow the instructions supplied with your specific medicine.
Mild side effects such as indigestion, headache or dizziness often settle within a few days, or once you stop taking naproxen. Naproxen usually leaves the body within a few days of your last dose. If side effects persist, get worse or affect your daily life, speak to your pharmacist or doctor. Get urgent help for any serious symptoms.
It’s best not to. Take naproxen with or just after a meal or snack, as this can help reduce indigestion and stomach discomfort. Swallow tablets whole with water, and don’t crush or chew gastro-resistant tablets. Taking it with food doesn’t remove the risk of stomach ulcers or bleeding, so always follow your prescribed dose.
It can. Drowsiness, tiredness and dizziness are recognised side effects of naproxen, although not everyone gets them. If you feel sleepy, dizzy or have blurred vision, don’t drive, cycle or use machinery until you feel well again. Alcohol can make drowsiness worse. Speak to your pharmacist if it continues.
Not exactly. Both are NSAIDs and work in the same way, so one isn’t simply “stronger” than the other. The main difference is that naproxen is longer-acting and usually taken twice a day, while ibuprofen is usually taken three or four times a day. Your prescriber or pharmacist will advise which is suitable for you.
Do not take ibuprofen alongside naproxen unless a healthcare professional specifically advises you to. Both are NSAIDs, and combining them can increase the risk of side effects, including stomach ulcers and bleeding. Paracetamol can sometimes be taken alongside naproxen for a short period, but check with a pharmacist or doctor first to make sure the combination is suitable for you.
References
eMC: Naproxen Tablets BP 250mg – Summary of Product Characteristics
eMC: Naproxen Tablets BP 250mg – Patient Information Leaflet
Medical disclaimer: This article is intended for general information and does not replace personalised medical advice, diagnosis or treatment. Naproxen may not be suitable for everyone. Always read the patient information leaflet supplied with your medicine and follow the advice of your doctor or pharmacist.
