Diclofenac

Sounds like 'dye-KLOE-fen-ak'

Diclofenac is an anti-inflammatory used to treat pain and inflammation. Find out how to take it safely and possible side effects. Diclofenac is also called Voltaren, Diclohexal or Apo-Diclo SR.

On this page, you can find the following information:

What is diclofenac?

Diclofenac is in a group of medicines known as non-steroidal anti-inflammatory drugs (NSAIDs). It's used to treat different types of pain such dental pain, period pain, bursitismigraine and pain resulting from injury or after surgery.

NSAIDs are also used to ease pain, swelling and stiffness associated with flare-ups of gout, osteoarthritis, rheumatoid arthritis and ankylosing spondylitis. NSAIDs block the inflammation process and in this way ease swelling and pain.

In New Zealand diclofenac comes as tablets, dispersible (dissolvable) tablets, suppositories and an injection.

  • Tablets comes as immediate release and slow release (SR).
  • The immediate release tablets are useful where immediate pain relief is required, and the slow release is more useful in reducing long term inflammation. 
  • The suppositories are useful when tablets are unsuitable, eg, for migraine which may involve vomiting. Learn more about suppositories. 

Lower strengths of diclofenac tablets and capsules (Voltaren Rapid®) can be bought from a pharmacy without a prescription.

Dose

  • The dose of diclofenac will be different for different people depending on its use. 
  • Immediate release tablets: The usual dose is 25 to 50 mg, 2 or 3 times a day.
  • Slow release tablets: The usual dose is 75 to 100 mg in 1 or 2 divided doses.   
  • Usually, you only need to take diclofenac for a short time, just while you have pain and swelling.

How to take diclofenac tablets or capsules

  • Tablets and capsules 
    • Swallow the tablets and capsules whole with a glass of water.
    • Don't crush or chew them.
    • If diclofenac causes stomach upset, take it with or soon after food.
  • Dispersible tablets
    • Dissolve the tablet in some water. Stir if necessary. 
    • After taking, rinse the container with water and drink this to ensure all the diclofenac dose is swallowed.
    • If diclofenac causes stomach upset, take it with or soon after food.
  • Stay hydrated while taking diclofenac to protect your kidneys. 
  • Avoid or limit alcohol while you're taking diclofenac. Alcohol can increase the risk of side effects like stomach upset.
  • Missed dose: If you forget to take a dose, take it when you next need pain relief and then continue as before. Don't take 2 doses together to make up for a missed dose.

When is taking diclofenac a concern?

For most people taking diclofenac is safe, but extra care is needed in some situations. For example if:

  • you have high blood pressure
  • you have heart or kidney problems or asthma
  • you're aged 65 years or older
  • you smoke.

It can be harmful if you take diclofenac when you are dehydrated or have been sick with diarrhoea (runny poos) or vomiting (being sick). Read more about the risks of NSAIDs.

When you should NOT take diclofenac 

Diclofenac should NOT be used in some situations as it can be harmful.

For example, if you:

  • have current or previous stomach problems such as ulcers or bleeding
  • are pregnant
  • have heart failure or chest pain (angina)
  • have had a stroke or heart attack
  • have chronic kidney disease
  • have had an allergic reaction (such as hives or trouble breathing) to ibuprofen, aspirin, or other similar medications (discuss with your healthcare provider)
  • are taking medicines to reduce blood clots (anticoagulants) such as warfarin, dabigatran or rivaroxaban
  • are also taking other anti-inflammatory medicines, eg, ibuprofen, naproxen (Naprosyn®) or celecoxib (Celebrex)
  • are taking some blood pressure medicines such as ACE inhibitors, ARBs, diuretics. Always check with your healthcare provider before taking NSAIDs.

Read more about the risks associated with NSAIDs

Taking diclofenac with other pain medicines

Don't take other anti-inflammatory medicines such as ibuprofen, naproxen or celecoxib while taking diclofenac.

It's safe to take diclofenac with paracetamol because they work differently.

Taking diclofenac with blood pressure medicines

Diclofenac interacts with some medicines, especially those used for high blood pressure, so check with your doctor or pharmacist before you start taking diclofenac.

Image credit: University of Otago

Taking NSAIDs together with blood pressure medicines can be harmful to your kidneys. This is called the ‘triple whammy’. If you are taking blood pressure medicines (ACE inhibitors or ARBs and diuretics) tell your doctor or pharmacist before starting diclofenac.

  • Examples of ACE inhibitors are captopril, cilazapril, enalapril, lisinopril, perindopril and quinapril.
  • Examples of ARBs are candesartan, irbesartan and losartan.
  • Examples of diuretics are furosemide, bumetanide, bendroflumethiazide, chlortalidone, indapamide, spironolactone, eplerenone and metolazone.

Read more about the triple whammy. 

What are the side effects of diclofenac?

Side effects What should I do?
  • Heartburn
  • Indigestion
  • Stomach discomfort
  • Runny poo (diarrhoea)
  • These are common and should settle within a few days.
  • Take diclofenac with food.
  • Talk to your doctor if they're ongoing.
  • Serious stomach problems such as really bad stomach pain, blood in your stool or black stools, cough or vomiting up blood or dark-coloured vomit.
  • Stop taking diclofenac.
  • Tell your doctor immediately or ring Healthline on 0800 611 116.
  • Chest pain
  • Shortness of breath or trouble breathing
  • Weakness in one part or side of your body
  • Slurred speech
  • Stop taking diclofenac.
  • Tell your doctor immediately or ring Healthline on 0800 611 116.
  • Swollen ankles, blood in your pee or not peeing at all – these can be signs of a kidney problem.
  • Stop taking diclofenac.
  • Tell your doctor immediately or ring Healthline on 0800 611 116.
 
  • Signs of an allergic reaction such as skin rash, itching, swelling of your lips, face and mouth or difficulty breathing
 
  • Stop taking diclofenac.
  • Tell your doctor immediately or ring Healthline on 0800 611 116.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.

Learn more

The following links have more information on diclofenac:

Diclofenac (Māori) NZ Formulary Patient Information

References

  1. Diclofenac sodium (systemic) New Zealand Formulary

Additional resources for healthcare professionals

NSAIDs and risk of cardiovascular events Medsafe, NZ, 2013
NSAIDs and acute kidney injury Medsafe, NZ, 2013
Reducing the risk of GI reactions with NSAIDs and/or COX-2 inhibitors Medsafe, NZ, 2013

Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 12 Sep 2022