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.

Type of medicine Also called
  • Analgesic (pain killer)
  • Anti-inflammatory (reduces pain and swelling)
  • Non-steroidal anti-inflammatory drug (NSAID)
  • Voltaren®
  • Voltaren SR ®
  • Voltaren-D® 
  • Diclofenac (Dr Reddy's)®
  • Diclofenac Sandoz®
  • Diclohexal®
  • Apo-Diclo SR®

What is diclofenac?

Diclofenac is in a group of medicines known as non-steroidal anti-inflammatory drugs (NSAIDs). It is used to treat different types of pain, such as pain from osteoarthritis, rheumatoid arthritis, ankylosing spondylitispainful periods (dysmenorrhoea), dental pain, migraine and pain resulting from injury or after surgery. It blocks the inflammation process and in this way eases swelling and pain. In New Zealand diclofenac is available as tablets, suppositories and can be given as an injection.   

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


  • The dose of diclofenac will be different for different people depending on your condition.
  • Usually, you only need to take diclofenac for a short time, only while you have pain and swelling.
  • The usual dose is 25–50 mg up to 3 times a day (every 8 hours) OR 75 mg up to twice a day (every 12 hours). 
  • Always take your diclofenac exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

How to take diclofenac

If you are unsure about how to take your diclofenac, ask your pharmacist. The following is a guide:

Formulation  How to take it
 Tablets and capsules
  • Swallow the tablets and capsules whole with a glass of water.
  • Do not crush or chew them.
  • Take diclofenac with food or immediately after food, to prevent stomach upset.
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.
  • Take diclofenac with food or immediately after food, to prevent stomach upset.
  • Remove the suppository from its wrapping.
  • Lie on your side and raise your knees to your chest.
  • Using your finger, gently push the suppository (blunt end first) into your rectum (bottom).
  • Remain lying down for a few minutes so that the suppository dissolves.
  • Wash your hands.
  • Try not go to the toilet and pass stools (poos) for at least an hour after inserting the suppository.

  • Limit or avoid alcohol while you are taking diclofenac. Alcohol can increase the risk of side effects like stomach upset. 
  • If you forget to take a dose, take it when you next need pain relief and then continue as before, taking your doses every 8 or 12 hours if needed. Do not take 2 doses together to make up for a forgotten dose.

Take care with diclofenac

For most people, taking diclofenac is safe. However, extra care is needed if you have high blood pressure, high cholesterol, diabetes, stomach ulcers or kidney problems or if you smoke. It can also be harmful if you take it when you are dehydrated or have been sick with nausea or vomiting. Discuss with your doctor whether taking diclofenac is suitable for you.

NSAIDs (except low-dose aspirin) increase the chance of a heart attack or stroke, which can lead to death. These serious side effects can occur even in the first weeks of using an NSAID and the risk may increase the longer you are taking them, and if you are taking high doses. Some other medicines contain NSAIDs, including those used for colds and the flu, so always read the labels and avoid taking multiple medicines that contain NSAIDs.

Precautions before taking diclofenac

  • Do you have high blood pressure or problems with your heart?
  • Do you have any problems with the way your kidneys or liver works?
  • Have you had stomach ulcers?
  • Do you have inflammatory bowel disease?
  • Are you pregnant, planning a pregnancy or breastfeeding?
  • Do you have any breathing problems or asthma?
  • Have you had an allergic reaction to a medicine, particularly to any other NSAID (such as aspirin, naproxen and ibuprofen) or a COX-2 such as celecoxib?

If so, it’s important that you tell your doctor before you start taking diclofenac. Sometimes a medicine isn’t suitable for a person with certain conditions or taking other medicines, or it can only be used with extra care.

What are the side effects of diclofenac?

Side effects What should I do?
  • Heartburn
  • Indigestion
  • Stomach discomfort
  • Take diclofenac with food.
  • Talk to your doctor if it is painful.
  • 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.
  • 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
  • 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
  • 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


  • Diclofenac interacts with some medicines, especially those used for high blood pressure, so check with your doctor or pharmacist before you start taking it.
  • Do not take other NSAIDs, such as ibuprofen or naproxen, or COX-2s, such as celecoxib, while taking diclofenac. This can increase your risk of side effects.
  • Taking NSAIDs together with medicines called ACE inhibitors or ARBs and diuretics (water pills) can be harmful to your kidneys. This is called the triple whammy. If you are taking ACE inhibitors or ARBs and diuretics, tell your doctor or pharmacist before starting diclofenac. 
    Examples of ACE inhibitors are captopril, cilazapril, enalapril, lisinopril, perindopril, quinapril and trandolapril.
    Examples of ARBs are valsartan, losartan and candesartan.
    Examples of diuretics are furosemide, bumetanide, bendroflumethiazide, chlortalidone, indapamide and metolazone.  
    Read more: The triple whammy SafeRx

Learn more

The following links have more information on diclofenac:

Diclofenac (Māori) New Zealand Formulary Patient Information


  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: 21 Mar 2019