Topical diclofenac: new preparation. Moderate efficacy in actinic keratosis

(1) Many treatments are available for actinic keratosis. The most widely used is cryotherapy. Topical application of 5% fluorouracil cream is a second-line option. (2) Marketing authorisation has been granted for a topical gel containing 3% diclofenac, a nonsteroidal antiinflammatory drug. The excipients include 2.5% hyaluronic acid. (3) Animal pharmacology studies and in vitro tests show that hyaluronic acid delays the transcutaneous uptake of diclofenac, leading to higher concentrations in the epidermis. (4) No comparative trials with fluorouracil or other drugs have been published. Five trials comparing 3% diclofenac topical gel with its excipient are available. They show that it takes at least two or three months of treatment for the lesions to disappear in one-third to one-half of patients. Indirect comparison suggests that diclofenac is less effective than fluorouracil in terms of lesion disappearance one month after the end of treatment. The subsequent risk of relapse is unknown. (5) Local adverse effects are numerous and frequent, and include contact dermatitis, skin rash, dry skin, desquamation, pruritus, local pain, and paresthesia. Adverse effects can be due to either diclofenac or to the excipient, and seem to be less intense than with topical fluorouracil. (6) Trials have shown that topical diclofenac is effective at a dose of 0.5 g of gel applied twice a day, but this precise dose is unlikely to be used as no measuring device is included in the packaging. (7) In practice, diclofenac topical gel is less effective than fluorouracil, and is only a moderately effective option when fluorouracil is poorly tolerated and when physical treatments such as cryotherapy fail.