Diclofenac for pain and inflammation

  • Diclofenac is a non-steroidal anti-inflammatory drug (also known as an NSAID).
  • Tell your doctor if you have ever had an allergic reaction to any other non-steroidal anti-inflammatory drugs.
Type of medicine Non-steroidal anti-inflammatory drug (NSAID)
Used for Pain and inflammation
Also called Diclomax®, Defenac®, Diclofex®, Dyloject®, Econac®, Enstar®, Flamrase®, Flamatak®, Motifene®, Rheumatac®, Rhumalgan®, Volsaid®, Voltarol®
Available as Tablets and dispersible tablets, gastro-resistant tablets, prolonged-release tablets and capsules, suppositories and injection

Anti-inflammatory painkillers like diclofenac are sometimes called non-steroidal anti-inflammatory drugs (NSAIDs), or just 'anti-inflammatories'. Diclofenac is used to treat painful conditions such as arthritis, sprains and strains, gout, migraine, dental pain, and pain after surgical operations. It eases pain and reduces inflammation.

Diclofenac works by blocking the effect of chemicals called cyclo-oxygenase (COX) enzymes. These enzymes help to make other chemicals in the body, called prostaglandins. Some prostaglandins are produced at sites of injury or damage, and cause pain and inflammation. By blocking the effect of COX enzymes, fewer prostaglandins are produced, which means pain and inflammation are eased.

There are two forms of diclofenac - diclofenac sodium and diclofenac potassium. The main difference between the two forms is that diclofenac potassium is absorbed into the body more quickly than diclofenac sodium. A quick action is useful where immediate pain relief is required, and a prolonged action is more useful in reducing inflammation.

Diclofenac is available on prescription. You can also buy a short course of diclofenac potassium at pharmacies, without a prescription, for pain such as headache, dental pain, period pain, backache and symptoms of cold and flu.

Diclofenac is not a suitable medicine for people who have heart disease (such as heart failure), or who have circulatory problems, or who have had a heart attack or a stroke. This is because it has been found that there is a small increased risk of heart attack and stroke in this group of people. Other anti-inflammatory medicines are more suitable for people with these conditions - ask your doctor or pharmacist for advice about an alternative medicine.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking diclofenac it is important that your doctor or pharmacist knows:

  • If you have asthma or any other allergic disorder.
  • If you have ever had a stomach or duodenal ulcer.
  • If you are pregnant, trying for a baby or breast-feeding.
  • If you are over 65 years of age.
  • If you have liver or kidney problems.
  • If you have a heart condition, or a problem with your blood vessels or circulation.
  • If you have high blood pressure.
  • If you have ever had blood clotting problems.
  • If you have a rare blood disorder known as porphyria.
  • If you have systemic lupus erythematosus (an inflammatory condition also called lupus or SLE).
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to any other NSAID (such as aspirin, ibuprofen, naproxen, and indometacin), or to any other medicine.
  • Before you start taking diclofenac, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about the specific brand of diclofenac you have been given and a full list of possible side-effects from taking it.
  • Take diclofenac exactly as your doctor has told you. Your doctor or pharmacist will tell you how much to take and when to take it. Your dose will also be on the label of the pack.
  • There are a number of different types of diclofenac tablets and capsules, such as immediate-release tablets, dispersible tablets, gastro-resistant tablets, and prolonged-release tablets or capsules. On the label of your pack, there will be instructions to tell you how you should take the type you have been given. Read and follow these directions carefully.
  • Try to take diclofenac at the same times each day to avoid missing any doses.
  • If you do forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
  • Your doctor will try to prescribe you the lowest dose for the shortest time to reduce the risk of side-effects. If you need to take diclofenac for a long time, your doctor may want to prescribe another medicine along with it to protect your stomach from irritation.
  • If you are taking diclofenac for a long-term condition, try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
  • If you have asthma, symptoms such as wheeze or breathlessness can be made worse by anti-inflammatories such as diclofenac. If this happens to you, you should stop taking diclofenac and see your doctor as soon as possible.
  • If you buy any medicines, check with a pharmacist that they are safe to take with diclofenac.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common diclofenac side-effects - these affect less than 1 in 10 people who take this medicine What can I do if I experience this?
Feeling or being sick Stick to simple or bland foods - avoid rich or spicy foods
Indigestion, heartburn, stomach pain, wind Try taking your dose after a meal if you are not already doing so. If the discomfort continues, speak with your doctor
Diarrhoea Drink plenty of water to replace the lost fluids
Feeling dizzy or sleepy If this happens do not drive or use tools or machines until your reactions return to normal
Other less common side-effects: headache, nervousness, mood changes, difficulty sleeping, vertigo (dizziness), and tinnitus (noises in the ear) If any of these become troublesome, speak with your doctor

Important: if you experience any of the following uncommon but serious symptoms, stop taking diclofenac and contact your doctor for advice straightaway:

  • If you pass blood or black stools, vomit blood, or have abdominal pains.
  • If you have any breathing difficulties such as wheeze or breathlessness.
  • If you have any signs of an allergic reaction such as swelling around your mouth or face, or an itchy skin rash.

If you experience any other symptoms which you think may be due to this medicine, discuss them with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Never take more than the prescribed dose. If you suspect that someone has taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • British National Formulary; 62nd Edition (Sep 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
  • Manufacturer's PIL, Voltarol® tablets,; Manufacturer's PIL, Voltarol® tablets, Novartis Pharmaceuticals UK Ltd, electronic Medicines Compendium. Dated June 2011.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Hannah Gronow
Document ID:
3357 (v25)
Last Checked:
20/02/2012
Next Review:
19/02/2015
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