Diclofenac is a medicine that reduces inflammation and pain.

It's used to treat aches and pains, as well as problems with joints, muscles and bones. These include:

• rheumatoid arthritis, osteoarthritis and gout
• sprains and strains in muscles and ligaments
• back pain
• ankylosing spondylitis - this causes inflammation of the spine and other parts of the body
• toothache
• migraine

Diclofenac comes as tablets, capsules and suppositories. These are available on prescription only.

It can also be given as an injection or as eyedrops. These are usually only given in hospital.

Diclofenac gel and plasters for joint pain are available to buy from pharmacies.

• 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
• lupus
• 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.

Diclofenac suppositories

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.

Diclofenac gel

• 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.

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)
• diarrhoea
• black poo or blood in your vomit - a sign of bleeding in your stomach
• headaches
• drowsiness
• 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

It's safe to take diclofenac with paracetamol or codeine.

Do not take diclofenac with similar painkillers - like aspirin, ibuprofen or naproxen - without talking to a doctor.

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:

• headaches
• 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.

These are not all the side effects of diclofenac. For a full list, see the leaflet inside your medicine packet.

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.

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.