Diclofenac gel: using a topical NSAID on sore joints and muscles

Diclofenac is an NSAID, and the NHS says that when you apply it to the skin as gel, plasters or patches it works in the same way as in tablet form, but only on the area you have treated. The UK product information for Voltarol Emulgel lists local symptomatic relief of pain and inflammation in trauma of the tendons, ligaments, muscles and joints, such as sprains, strains and bruises, in localised soft tissue rheumatism, and in osteoarthritis of superficial joints such as the knee.

The NHS notes that gels and plasters can be bought from pharmacies for joint pain, while tablets are prescription-only, and that diclofenac does not work for some types of pain, such as nerve pain.

Gently squeeze a small amount from the tube or dispenser and rub it slowly into the painful or swollen area. The NHS describes an amount about the size of a cherry or walnut, 2 to 4 grams, depending on the area, used 2 to 4 times a day according to strength, with at least 4 hours between applications if using it 3 or 4 times, and never more than 4 times in any 24 hours.

Wipe the hands with a paper towel and wash them afterwards unless the hands are the area being treated; wipe off excess gel with a paper towel and dispose of it in household waste. Let the gel dry for a few minutes before applying a bandage. It can be used with non-occlusive bandages but not under an airtight dressing. Adults and children aged 14 and over use the same adult range, and it is contraindicated in children under 14.

The NHS says gel typically takes 1 to 2 days to work, and for arthritis you may need to use it for up to 7 days on the painful joint to feel the full effect. When you stop, the effects wear off after 1 or 2 days.

The product information recommends reviewing treatment after 14 days for injuries and soft tissue rheumatism, and after 4 weeks for osteoarthritis. If pain persists beyond those points, the next step is a review rather than more gel.

Local effects are the usual ones: rash, eczema, redness, dermatitis and itching are common, with blistering dermatitis rare and photosensitivity reactions very rare. The NHS suggests moisturising dry or irritated skin, using the gel less often (once a day, or every other day) or pausing for a few days, and an over-the-counter antihistamine for itching after checking with a pharmacist. Stop using the gel if a rash develops after application.

Protect the treated area from strong sunlight and use sun cream (SPF 30 or above), and avoid sunlamps and sunbeds. Rarely, systemic NSAID effects can occur if a lot is used on a large area of skin, and bronchospasm can be precipitated in people with asthma. If the gel is swallowed, call NHS 111.

The product information lists contraindications of asthma, angioedema, urticaria or acute rhinitis precipitated by aspirin or other NSAIDs, hypersensitivity to diclofenac or any ingredient, the third trimester of pregnancy, and use in children under 14. Using systemic NSAIDs at the same time warrants caution, because untoward effects could increase. Some gut bleeding has been reported in isolated cases in people with a significant history.

The NHS says to tell your doctor or pharmacist about any previous reactions to aspirin or NSAIDs, stomach ulcers, heart, kidney or liver problems, and asthma.

Diclofenac is not usually recommended in pregnancy, and the NHS says paracetamol is generally the first-choice painkiller. The product information states the third trimester is a contraindication because NSAIDs can affect the baby's heart, lungs and kidneys and the mother's labour. It passes into breast milk in small amounts, and the NHS says you can use diclofenac while breastfeeding, taking care that your baby does not touch treated skin and washing your hands before picking the baby up.

Because systemic absorption from topical use is very low, interactions are unlikely, but tell a pharmacist about regular NSAIDs, anticoagulants or other medicines you use.