- Take diclofenac tablets or capsules with a meal or snack, or just after eating.
- It's best to take the lowest dose of diclofenac for the shortest time to control your symptoms.
- The most common side effects are headaches, dizziness, stomach pain, feeling or being sick, diarrhoea and rashes.
- Diclofenac tablets come as either diclofenac potassium or diclofenac sodium. They work as well as each other.
- Diclofenac is also called by the brand names Voltarol, Dicloflex, Econac and Fenactol.
Most adults can take diclofenac.
Children may be prescribed diclofenac to treat joint problems. Diclofenac tablets, capsules and suppositories are suitable for children aged 1 year and above.
Diclofenac isn't suitable for certain people.
Tell your doctor or pharmacist if you have:
- had an allergic reaction to diclofenac or any other medicines in the past
- an allergy to aspirin or other non-steroidal anti-inflammatory medicines (NSAIDs) such as ibuprofen or naproxen
- ever had signs of asthma (wheezing), a runny nose, swelling of the skin (angioedema) or a rash after taking NSAIDs
- ever had stomach ulcers, bleeding in the stomach or intestines, or a hole in your stomach
- high blood pressure (hypertension)
- heart failure, or severe liver disease or kidney disease
- Crohn's disease or ulcerative colitis
- a blood clotting disorder
Tell your doctor or pharmacist if you're pregnant, planning to become pregnant, or breastfeeding.
You'll usually take diclofenac tablets, capsules or suppositories 2 to 3 times a day.
The standard dose is 75mg to 150mg a day, depending on what your doctor prescribes for you. Follow your doctor's advice on how many tablets to take, and how many times a day.
If your doctor prescribes diclofenac for your child, they'll use your child's weight to work out the right dose for them.
If you have pain all the time, your doctor may recommend slow-release diclofenac tablets or capsules. It's usual to take these either once a day in the evening, or twice a day.
If you're taking slow-release diclofenac twice a day, leave a gap of 10 to 12 hours between your doses.
How to use them
Tablets and capsules
Swallow the diclofenac tablets or capsules with a glass of water or milk. Swallow them whole - do not crush, break or chew them.
Always take your diclofenac tablets or capsules after a meal or snack, or with a drink of milk. They'll be less likely to upset or irritate your stomach.
Suppositories are medicine that you push gently into your back passage (anus).
- Go to the toilet beforehand if you need to.
- Wash your hands before and after using the medicine. Also clean around your back passage with mild soap and water, rinse and pat dry.
- Unwrap the suppository.
- Gently push the suppository into your back passage (anus) with the pointed end first. It needs to go in about 3 centimetres (1 inch).
- Sit or lie still for about 15 minutes. The suppository will melt inside your back passage. This is normal.
- Gently squeeze out the tube - or press firmly and evenly on the nozzle of the dispenser - to get a small amount of gel.
- Put the gel on the painful or swollen area and slowly rub it in. It may feel cool on your skin. Wash your hands afterwards.
You'll usually use the gel 2 to 4 times a day, depending on how strong it is. Check the packaging for more information or speak to your pharmacist.
If you're using the gel twice a day, use it once in the morning and once in the evening. If you're using it 3 or 4 times a day, wait at least 4 hours before putting on any more.
Do not use diclofenac gel more than 4 times in any 24-hour period.
The amount of gel you need will vary. It depends on the size of the area you want to treat. You'll usually use an amount about the size of a 1 penny or 2 pence piece (2 to 4 grams).
Diclofenac plasters and patches
- Stick a medicated plaster or patch over the painful area twice a day - once in the morning and once in the evening. Apply gentle pressure with the palm of your hand until it's completely stuck to your skin.
- Treat only 1 painful area at a time. Do not use more than 2 medicated plasters in any 24-hour period.
- When you want to take the plaster or patch off, it helps to moisten it with some water first. Once you have taken it off, wash the affected skin and rubit gently in circular movements to remove any leftover glue.
What if I forget to take it?
Take your forgotten dose as soon as you remember, unless it's nearly time for your next dose. In this case, skip the missed dose and take your next dose as normal.
Never take a double dose to make up for a forgotten dose.
If you often forget doses, 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 take too much?
Taking too many diclofenac tablets, capsules or suppositories can be dangerous. It can cause side effects such as:
- stomach ache
- feeling or being sick (vomiting)
- black poo or blood in your vomit - a sign of bleeding in your stomach
- ringing in your ears (tinnitus)
If you accidentally take too much diclofenac, contact your doctor straight away. If you need to go to hospital, take the diclofenac packet or leaflet inside it plus any remaining medicine with you.
If you use too many plasters or too much gel by mistake, it's unlikely to do you any harm. But if you use too much and get any side effects, tell your doctor straight away
Diclofenac, aspirin, ibuprofen and naproxen all belong to the same group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs). Taking diclofenac together with other NSAIDs may increase your chances of getting side effects like a stomach ache.
NSAIDs are also used in medicines you can buy from pharmacies - for example, cough and cold remedies. Before taking any other medicines, check the label to see if they contain aspirin, ibuprofen or other NSAIDs.
Like all medicines, diclofenac can cause side effects, although not everyone gets them.
Common side effects
Common side effects of diclofenac tablets, capsules and suppositories happen in more than 1 in 100 people.
Talk to your doctor or pharmacist if these side effects bother you or don't go away:
- feeling dizzy or vertigo
- stomach ache, wind or loss of appetite
- feeling sick (nausea)
- being sick (vomiting) or diarrhoea
- mild rash
You're less likely to have side effects with diclofenac gel or plasters. This is because not as much of the medicine gets into your body. But you may still get the same side effects, especially if you use a lot on a large area of skin.
In addition, using diclofenac gel or plasters can affect your skin. It can make your skin:
- more sensitive to sunlight than normal
- develop a rash where the gel or plaster has been applied
- dry or irritated (eczema)
- itchy or inflamed (dermatitis)
Serious side effects
These serious side effects are rare and happen in less than 1 in 1,000 people.
Call your doctor straight away if:
- you have blood in your vomit or black poo - these could be signs of bleeding in your stomach or gut
- you have severe indigestion, heartburn or stomach pain, vomiting or diarrhoea - these can be signs of an ulcer or inflammation in your stomach or gut
- your skin or the whites of your eyes turn yellow - this can be a sign of liver problems
- you have a raised, itchy rash, or swollen or puffy skin - these can be signs of hives (urticaria) or oedema
- you have breathlessness, tiredness and swollen legs or ankles - these can be signs of heart failure
- you have chest pain, shortness of breath, feeling weak or lightheaded, or an overwhelming feeling of anxiety - these can be signs of a heart attack
- you have weakness on one side of your body, trouble speaking or thinking, loss of balance or blurred eyesight - these can be signs of a stroke
If you suspect that you or someone else is having a stroke, phone 999 immediately and ask for an ambulance.
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction to diclofenac.
Contact a doctor straight away if:
- you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
- you're wheezing
- you get tightness in the chest or throat
- you have trouble breathing or talking
- your mouth, face, lips, tongue or throat start swelling
These are warning signs of a serious allergic reaction. A serious allergic reaction is an emergency.
These are not all the side effects of diclofenac. For a full list, see the leaflet inside your medicine packet.
You can report any suspected side effect to the UK safety scheme.
What to do about:
- headaches - make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend an alternative painkiller. Headaches should usually go away after the first week of taking diclofenac. Talk to your doctor if they last longer than a week or are severe.
- feeling dizzy or vertigo - if you feel dizzy or unsteady, stop what you're doing and sit or lie down until you feel better. Do not drive or use tools or machinery if you're feeling dizzy or lightheaded. As your body gets used to diclofenac, these side effects should wear off.
- stomach ache, wind or loss of appetite - try not to eat foods that cause wind (like peas, lentils, beans and onions). Eat smaller meals, eat and drink slowly, and exercise regularly.
- feeling sick (nausea) - take diclofenac with or after a meal or snack. It may also help if you avoid rich or spicy food.
- being sick (vomiting) or diarrhoea - drink plenty of water or other fluids. If you're being sick, try small frequent sips of water. Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee. Do not take any other medicines without speaking to a pharmacist or doctor.
- a mild rash and dry or irritated, itchy or inflamed skin - an emollient cream or ointment can be used to moisturise, soothe and hydrate the affected area. If it does not get better within a week or you're worried, speak to a pharmacist or doctor.
- skin being more sensitive to sunlight - stay out of bright sun and use a high factor sun cream (SPF 15 or above), even on cloudy days. Do not use a sunlamp or sunbeds.
Diclofenac is not generally recommended in pregnancy or while breastfeeding.
This is because diclofenac has been linked with a small risk of problems for your unborn baby if you take it in early or late pregnancy.
Your doctor will only prescribe diclofenac for you while you're pregnant or breastfeeding if the benefits of taking the medicine outweigh the risks.
There may be other treatments that are safer for you. Paracetamol is the best painkiller to take during pregnancy.
Diclofenac and breastfeeding
Diclofenac isn't usually recommended if you're breastfeeding
It's safer to take another anti-inflammatory medicine, such as ibuprofen.
Tell your doctor if you're:
- trying to get pregnant
There are some medicines that interfere with the way diclofenac works. Tell your doctor if you're taking:
- other anti-inflammatory medicines, such as aspirin or ibuprofen
- antibiotics, such as ciprofloxacin, levofloxacin, moxifloxacin, nalidixic acid, norfloxacin or ofloxacin
- blood thinners, such as warfarin
- medicines for heart problems, such as digoxin, and medicines for high blood pressure
- medicines to lower cholesterol, such as colestipol and cholestyramine
- medicines to treat seizures, such as phenytoin
- medicines that reduce the activity of your immune system, such as ciclosporin or tacrolimus
- selective serotonin reuptake inhibitor (SSRI) antidepressants like citalopram or sertraline
- steroid medicines, such as hydrocortisone or prednisolone
- tablets that make you pee more, such as furosemide and bumetanide
- lithium, which is used to treat mental health problems
- methotrexate, which is used to treat some inflammatory diseases and cancers
- mifepristone, which is used for ending a pregnancy (abortion)
- zidovudine, which is used to treat HIV
Mixing diclofenac with herbal remedies or supplements
It's not possible to say that complementary medicines or herbal remedies are safe to take with diclofenac.
They're not tested in the same way as prescription medicines or medicines sold in pharmacies. They're generally not tested for the effect they can have on other medicines.
For safety, tell your doctor and pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.
How does diclofenac work?
Diclofenac is a non-steroidal anti-inflammatory drug (NSAID). It works by reducing hormones that cause inflammation and pain in the body.
When you apply diclofenac gel to your skin, it works in the same way as when you take it as a tablet or capsule. But the gel only works on the area you have put it on.
When will I feel better?
Diclofenac takes 20 to 30 minutes to work if you take it as tablets or capsules.
Suppositories take a few hours to work. There's no difference in how well the tablets, capsules or suppositories work. The doses of diclofenac are the same for each.
If you're using diclofenac gel on your skin, it usually takes 1 to 2 days to work. For arthritis, you may need to use the gel for up to 7 days on the painful joint in order to feel the full effect.
How long will I take it for?
Depending on why you're taking diclofenac, you may only need to take it for a short time. For example, if you have a sore back or toothache, you may only need to take diclofenac for a day or two.
You may need to take it for longer if you have a long-term condition, such as rheumatoid arthritis.
If you need to take diclofenac for a long time, your doctor may prescribe a medicine to protect your stomach from side effects. It's best to take the lowest dose of diclofenac for the shortest time to control your symptoms.
Talk to your doctor if you're unsure how long you need to take it for.
Is it safe to take long term?
Diclofenac can cause an ulcer in your stomach or gut if you take it for a long time or in big doses.
It's best to take the lowest dose that works for the shortest possible time.
If you need to take diclofenac very often or you're taking a big dose, talk to your doctor about your pain.
Are there other painkillers I can try?
The type of painkiller that's best depends on what type of pain you have and the cause of your pain.
If you need to take an NSAID long term, your doctor or pharmacist may recommend ibuprofen or naproxen instead of diclofenac. This is because they're less likely to cause heart problems.
Your doctor may also be able to prescribe a stronger painkiller, such as higher dose co-codamol or codeine.
Diclofenac doesn't work for some types of pain, such as nerve pain. Your doctor will have to prescribe a different medicine to relieve nerve pain.
Why do I need to be careful about stomach ulcers?
Diclofenac can cause an ulcer in your stomach or gut if you take it for a long time or in big doses, or if you're elderly or in poor general health.
Your doctor may tell you not to take diclofenac if you have a stomach ulcer or have had one in the past. If you need to take diclofenac but you're at risk of getting a stomach ulcer, your doctor may prescribe another medicine for you to take alongside diclofenac to protect your stomach.
It's important to take your diclofenac tablets or capsules after a meal or snack, or with a drink of milk. They'll be less likely to upset or irritate 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 diclofenac as it's gentler on your stomach.
If you think you may have symptoms of a stomach ulcer, stop taking diclofenac and contact your doctor.
Is it addictive?
No, diclofenac is not addictive, but it's important to always take it as prescribed.
What will happen if I stop taking it?
Once you stop taking diclofenac tablets or capsules, or stop using the suppositories, the effects will wear off after about 15 hours.
Will it affect my fertility?
Taking anti-inflammatory medicines, like diclofenac, in large doses or for a long time can affect ovulation in women. This may make it more difficult to get pregnant.
Do not take diclofenac if you're trying to get pregnant, or if you're having tests for infertility.
Paracetamol is a better painkiller in these situations.
Will it affect my contraception?
Can I drink alcohol with it?
Yes, you can drink alcohol while taking diclofenac. But drinking too much alcohol may irritate your stomach.
Try to keep to the recommended guidelines of no more than 14 units of alcohol a week. A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
Is there any food or drink I need to avoid?
No, you can eat and drink normally while taking diclofenac.
Can I drive or ride a bike?
It happens rarely, but some people can feel tired, dizzy or sleepy when they take diclofenac. They may also have problems with their eyesight.
If diclofenac affects you in this way, do not drive or ride a bike until it passes and you feel OK again.