Diclofenac belongs to a class of medicines called non-steroidal anti-inflammatory drugs (NSAIDs), it was first launched as Voltarol. It helps to reduce inflammation and decrease pain. Diclofenac works by blocking the production of chemicals in the body that cause inflammation, pain, stiffness, tenderness, swelling and increased temperature. By reducing inflammation diclofenac can help to improve the range of movement in muscles and joints.
There are two forms of diclofenac - diclofenac sodium and diclofenac potassium. The main difference between the two forms is that diclofenac potassium is absorbed into the body more quickly than diclofenac sodium. A quick action is useful where immediate pain relief is required, and a prolonged action is more useful in reducing inflammation.
Diclofenac works by blocking the effect of chemicals called cyclo-oxygenase (COX) enzymes. These enzymes help to make other chemicals in the body, called prostaglandins. Some prostaglandins are produced at sites of injury or damage, causing pain and inflammation. Blocking the effect of COX enzymes means fewer prostaglandins are produced. This results in a reduction of pain and inflammation.
Before you start taking diclofenac, read the manufacturer's printed information leaflet contained inside the pack. The leaflet will give you more information about the specific brand of diclofenac you have been given and a full list of possible side effects.
Take diclofenac exactly as instructed. Your doctor or pharmacist will tell you how much to take and when to take it. Some of the usual doses for common conditions are listed below:
Usual Adult Dose for Pain:
Diclofenac potassium: 50mg orally 3 times a day. In some patients an initial dose of 100mg of diclofenac potassium, followed by 50mg doses, will provide better relief.
Usual Adult Dose for Rheumatoid Arthritis:
Diclofenac sodium: 50mg orally 3 to 4 times a day or 75mg orally twice a day.?Diclofenac extended-release: 100mg orally once a day.
Usual Adult Dose for Ankylosing Spondylitis:
Diclofenac sodium: 25mg orally 4 times a day. An additional 25mg dose may be taken at bedtime, if necessary.
Try to take diclofenac at the same times each day to avoid missing any doses. If you do forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose.
Do not take two doses together to make up for a forgotten dose.
Common side effects of diclofenac may include:
- Upset stomach, mild heartburn or stomach pain, bloating, gas;
- Mild diarrhea, constipation;
- Dizziness, mild headache;
- Mild skin rash;
- Ringing in your ears.
This is not a complete list of side effects and others may occur. Call your doctor or pharmacist for advice about side effects.
Much less common (only 1 in 10,000 people suffer these) are:
- Breathing problems - seek immediate medical advice if you have breathing difficulties, bronchospasm, an asthma attack or if your asthma becomes worse;
- Gastrointestinal problems such as ulcers or bleeding - these may be fatal. Seek medical advice if you have melaena, blood in vomit or diarrhoea or if you have any other unusual stomach problems;
- Liver problems such as jaundice. You should particularly look out for: skin rash or rashes. If this occurs you must seek medical advice;
- Lowered blood pressure;
Patients with serious underlying heart conditions, such as heart failure, heart disease, circulatory problems or a previous heart attack or stroke should not take diclofenac. This follows completion of a European review, which found a small increased risk of heart attack and stroke. Patients with certain cardiovascular risk factors such as high blood pressure, raised cholesterol, diabetes and smoking should only use diclofenac following a discussion with their doctor or pharmacist.
Diclofenac should not be used by anyone who:
- Is allergic to diclofenac or to any of the ingredients of the medication
- Is breast-feeding
- Is currently taking other NSAIDs
- Is in the third trimester of pregnancy (after 28 weeks)
- Is planning to have or recently had heart bypass surgery
- Is under 16 years of age
- Currently has or recently had inflammatory diseases of the stomach and intestines, such as stomach or intestinal ulcer or ulcerative colitis
- Has bleeding in the brain or a bleeding disorder
- Has had an allergic reaction to ASA or other anti-inflammatory medications
- Has high levels of potassium in the blood
- Has severe uncontrolled heart failure
- Has severely impaired or deteriorating kidney function
- Has significant liver impairment or liver disease
The patient information leaflet (PIL) is a leaflet containing specific information about medical conditions, doses and side effects. You can download a copy of the PIL here:
Patient Info Leaflet