Like all medicines, this medicine can cause side effects, although not everybody gets them.
Skin rash (nettle rash); breathing problems (wheezing); swelling of the face; runny nose (allergic rhinitis). These symptoms indicate that you may be allergic to Diclofenac sodium gel.
If any of the following common side effects are severe or last for more than a few days, you should stop using Diclofenac sodium gel and contact your doctor: itching, skin rash, skin redness, inflammation, contact dermatitis, pain and blistering.
Other common side effects: (may affect up to 1 in 10 people)
Irritation or tingling at the site of treatment, conjunctivitis, allergy, a painful sensation when the skin is touched, pins and needles, muscle stiffness, inflammation of the skin, eczema, dry skin, swelling, skin rash (including scaling or blistering), sagging of the skin and skin ulcer.
Uncommon side effects: (may affect up to 1 in 100 people)
Eye pain, weeping/dry eyes, abdominal pain, diarrhoea, feeling sick, hair loss, facial swelling, excessive bleeding or oily skin, a measles-like skin rash.
Rare side effects: (may affect up to 1 in 1,000 people)
Skin inflammation with large blisters
Very rare side effects: (may affect up to 1 in 10,000 people)
Bleeding from your stomach, kidney problems, breathing difficulties (asthma), all types of hypersensitivity reactions (including nettle rash, rapid swelling of the skin and mucous membranes), infected skin rash, skin sensitivity to sunlight.
Temporary hair discolouration at the application site has been reported. This is usually reversed after stopping treatment.