Cumulative irritancy comparison of adapalene gel 0.1% versus other retinoid products when applied in combination with topical antimicrobial agents.

This randomized, investigator-blinded study evaluated the level of skin tolerance to adapalene gel 0.1%, tretinoin cream 0.025%, or tretinoin microsphere gel 0.1% when applied in combination with clindamycin phosphate lotion 1%, erythromycin gel 2%, benzoyl peroxide gel 5%, or erythromycin-benzoyl peroxide gel. A total of 37 subjects underwent daily application of the topical antimicrobial and retinoid products to sites on their upper back under protective patches for approximately 16 hours each day; Friday patches were left in place over the weekend. Testing continued daily for 3 weeks or until discontinuation caused by a severe adverse reaction to any of the test products or to the patch. Adapalene gel 0.1% demonstrated statistically significantly (P <.001) less irritation after repeated application under occlusive conditions than tretinoin cream 0.025% or tretinoin microsphere gel 0.1%. Moreover, the application of adapalene gel 0.1% under these conditions, concomitantly with various antimicrobial agents, was safe and well tolerated in this subject population. In view of its low irritation potential and its efficacy, adapalene gel 0.1%, in combination with antimicrobial agents should be considered for the treatment of acne vulgaris.

Cumulative irritancy potential of adapalene cream 0.1% compared with adapalene gel 0.1% and several tretinoin formulations.

Thirty-one subjects (8 males and 23 females; mean age, 49.8 years) were enrolled in a single-center study to assess the irritancy potential of adapalene (Differin cream 0.1% and Differin gel 0.1%) and tretinoin (Avita cream 0.025%, Retin-A cream 0.025%, Retin-A cream 0.05%, Retin-A Micro gel 0.1%, and generic cream 0.025%) as compared with white petrolatum when applied under occlusive conditions. All test materials were applied randomly under occlusion to sites located on the upper area of the subject's back under protective patches. All patches were applied to the same sites unless the degree of reaction to a test product or the adhesive necessitated removal (grade 3). Each test material was applied daily, Monday through Friday, for approximately 24 hours, with the Friday patches left in place over the weekend. Twenty-six of the 31 subjects (84%) completed the study. No subject discontinued because of an adverse event. Five subjects voluntarily discontinued the study early for reasons unrelated to study treatment (4 subject request and 1 lost to follow-up). In the statistical comparison of the 7 test products, the mean cumulative irritancy index of both adapalene cream 0.1% and gel 0.1% was statistically significantly (P<.05) lower than for all of the tretinoin products used and was not significantly higher than the negative control product (white petrolatum).