3% diclofenac in 2.5% hyaluronic acid (Solaraze) does not induce photosensitivity or phototoxicity alone or in combination with sunscreens

Abstract

Topical treatment with 3% diclofenac in 2.5% hyaluronic acid (Solaraze) has been extensively documented for the treatment of actinic keratoses (AK). Since sun protection is a vital part of AK management, two Phase IV studies were carried out to investigate the phototoxicity and photosensitisation potential of 3% diclofenac in 2.5% hyaluronic acid in combination with sunscreens. Patches of 3% diclofenac in 2.5% hyaluronic acid and control were applied under occlusion to the backs of healthy volunteers aged 18-65. In the phototoxicity study (n = 32), a single application followed by administration of the sunscreens and exposition with ultraviolet (UV) were done, whereas in the photosensitisation study, application was repeated twice weekly for three weeks, then once after a two-week rest phase. The erythema reaction was recorded, together with other local skin reactions. In both analyses, areas treated with 3% diclofenac in 2.5% hyaluronic acid in combination with sunscreens had the lowest incidence of erythema reactions, indicating that it was well tolerated when used in conjunction with sunscreen products, and with exposure to UV irradiation. The results showed that no phototoxic or photosensitisation reactions occurred with 3% diclofenac in 2.5% hyaluronic acid, either alone or in combination with sunscreens.