Diclofenac gel for actinic keratoses

What is diclofenac gel in hyaluronic acid?

Topical 3% diclofenac gel in 2.5% hyaluronic acid (Solaraze®, Bioglan Pharma, Florida USA) is used as a field treatment for actinic keratoses (AKs). It is available in the US, Canada and several countries in the European Union, but it is not marketed in New Zealand (2015).

How does diclofenac gel work?

The active ingredient of the gel, diclofenac sodium, is a non-steroidal anti-inflammatory drug (NSAID). NSAIDs provide anti-inflammatory and anti-neoplastic (anti-cancer) benefits.

• It is not fully understood how diclofenac gel works in treating AKs.
• Diclofenac is a potent inhibitor of inducible cyclo-oxygenase (COX-2), resulting in a reduction of prostaglandin synthesis.
• Sun damage and AKs have been linked with raised prostaglandins in exposed skin.

How is diclofenac gel administered?

Treatment is usually undertaken during the winter months. Diclofenac gel is only for use on the skin and contact with eyes should be avoided.

• The gel should be stored at room temperature.
• Determine which areas are to be treated with diclofenac gel. The amount of diclofenac gel needed depends upon the size of the lesion site.
• Normally, 0.5 g of gel (one fingertip unit) is used on each 5 cm x 5 cm lesion site.
• Extra gel should not be applied if an application is omitted.
• The gel is applied twice daily for between 60–90 days and is then discontinued.

After treatment

• Wash hands after applying diclofenac gel.
• Avoid sun exposure, sunscreens, cosmetics and other topical medications.

Keratoses may continue to improve for up to 30 days after stopping treatment. Any lesions that do not respond to treatment should be re-evaluated.

Precautions when using diclofenac gel for actinic keratoses

Diclofenac sodium gel should not be used or should be used with caution by patients with any of the following conditions:

• Known hypersensitivity to diclofenac, benzyl alcohol, polyethylene glycol monomethyl ether 350 and/or hyaluronate sodium.
• Sensitivity or allergy to aspirin.
• Active peptic ulcer or a severe disorder of kidney or liver.
• Open skin wound or infected skin.

Anaphylactoid reactions may occur in patients without prior exposure to diclofenac.

Potential drug interactions with diclofenac gel

• Specific interaction studies between diclofenac sodium gel and other topical or oral agents have not been performed.
• Some diclofenac enters the blood stream after application to the skin.
• There is an increased risk of adverse effects if oral NSAIDs or aspirin are taken at the same time.

What adverse events can diclofenac gel cause?

Generally, adverse events have been mild-to-moderate in severity. The most common reported adverse events (>1%) are application site reactions, including itch, dry skin, redness and contact dermatitis

Use in pregnancy

• The safety of diclofenac sodium gel has not been established during pregnancy.
• Diclofenac should not be used during pregnancy unless the benefits to the mother justify the potential risk to the fetus.
• Diclofenac should be avoided in late pregnancy because premature closure of the ductus arteriosus of the fetus may occur.

Use in nursing mother

• Many drugs are excreted in human milk. It is not known whether diclofenac or its metabolites are excreted in human milk.
• Nursing mothers should avoid using diclofenac gel.

Paediatric use

• The safety and effectiveness of diclofenac gel have not been established in children.
• Actinic keratoses rarely affect children.