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.
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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 spondylitis, painful 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:
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- 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?
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- 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
The following links have more information on diclofenac:
- 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