Sounds like 'dye-KLOE-fen-ak'

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

Type of medicineAlso 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 one of 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 diclofenac 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 stomach side effects. 
  • It is not harmful if you miss your diclofenac dose. If you miss a dose, take it when you remember, with or after food. Do not take double the amount of tablets.

Take care

  • For most people, taking diclofenac is safe. However, extra care is needed if you have high blood pressure, high cholesterol, diabetes, your kidney do not work very well or 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, either of which can lead to death. These serious side effects can occur as early as the first weeks of using an NSAID and the risk may increase the longer you are taking an NSAID.
  • 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.
  • Many medicines contain NSAIDs, including those used for colds, flu, so it is important to read the labels and avoid taking multiple medicines that contain NSAIDs.

Possible side effects

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

Side effectsWhat should I do?
  • Heartburn
  • Indigestion
  • Stomach discomfort
  • Take diclofenac with food.
  • 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 important medications, so check with your doctor or pharmacist.
  • Do not take other NSAID medication such as ibuprofen or naproxen while you are  taking diclofenac.

Learn more

New Zealand Formulary Patient Information:

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr J Bycroft. Health Navigator NZ Last reviewed: 13 Jul 2015