Sounds like 'dye-KLOE-fen-ak'

Easy-to-read medicine information about diclofenac – what it is, how to take it safely and possible side effects.

Type of medicine Also called
  • Analgesic (pain killer)
  • Anti-inflammatory
  • Belongs to a group of medicines known as non-steroidal anti-inflammatory drugs (NSAIDs)
  • Voltaren®
  • Diclofenac (Dr Reddy's)®

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 muscle pain, dental pain, migraine and pain resulting from injury or after surgery. Diclofenac also helps to ease redness and swelling caused by injury. It blocks the inflammation process in your body and in this way eases swelling and pain.


  • The usual dose of diclofenac is 25 or 50 milligrams every 8 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

  • Take diclofenac with food or immediately after food, to prevent stomach upset.
  • Swallow the tablets with a full glass of water. Do not crush or chew them.
  • Usually, you may only need to take diclofenac for a short period of time, while you have pain or swelling.
  • Limit or avoid alcohol while you are taking diclofenac. Alcohol can increase the risk of side effects. 
  • It is not harmful if you miss the occasional dose of diclofenac. If you miss a dose, take it when you remember. But, if it is nearly time for your next dose, just take the next dose at the right time.  Do not take double the 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. Discuss with your doctor if taking diclofenac is suitable for you.    
  • Non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) such as diclofenac 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 NSAIDs and the risk may increase the longer you are taking them. The risk appears greater at higher doses; use the lowest effective amount for the shortest possible time. Seek medical attention immediately if you experience symptoms such as:
    • chest pain
    • shortness of breath or trouble breathing
    • sudden weakness or numbness in one part or side of the body
    • sudden slurred speech.
  • Some other medicines contain NSAIDs, including those used for colds, 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?
  • Are you pregnant or breast-feeding?
  • Do you have any breathing problems?

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.

Possible side effects

Like all medicines, diclofenac can cause side effects, although not everyone gets them.

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 the stool or black stools, cough or vomit up blood or dark coloured vomit.
  • Tell your doctor immediately or ring HealthLine on 0800 611 116
  • Allergic reaction such as skin rash, itching, swelling of the lips, face, and mouth or difficulty breathing
  • 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 the body
  • Slurred speech
  • Tell your doctor immediately or ring HealthLine on 0800 611 116


  • 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 while taking diclofenac. This can increase your risk of side effects.
  • Taking NSAIDs together with medicines called ACE inhibitors and diuretics (water pills) can be harmful to your kidneys. If you are taking ACE inhibitors 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 diuretics are furosemide, bumetanide, bendroflumethiazide, chlortalidone, indapamide and metolazone.  
    Read more: The triple whammy SafeRx

Learn more

New Zealand Formulary Patient Information: Diclofenac


  1. Diclofenac sodium (systemic) New Zealand Formulary
Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr J Bycroft. Health Navigator NZ Last reviewed: 31 Jul 2017