Department

Therapeutics for the Clinician

Cumulative Irritation Comparison of Adapalene Gel and Solution With 2 Tazarotene Gels and 3 Tretinoin Formulations

Greenspan A, Loesche C, Vendetti N, Georgeian K, Gilbert R, Poncet M, Baker MD, Soto P

Cutis. 2003;72:76-81.

Forty-two subjects with normal skin were enrolled in a single-center study to assess the cumulative irritancy potential of adapalene (Differin® gel 0.1% and Differin solution 0.1%) compared with tazarotene (Tazorac® gels 0.05% and 0.1%), tretinoin (Retin-A Micro® gel 0.1%, Avita® cream 0.025%, and Avita gel 0.025%), and white petrolatum (negative control). All test materials were applied randomly, under occlusion, to sites located on either side of the midline—the mid thoracic area of the subjects’ backs. All patches were applied daily, Monday through Friday, to the same sites, unless the degree of reaction to a test product or adhesive necessitated removal (grade 3).

Thirty-eight of the 42 subjects (90.5%) completed the study. Thirty-four of those 38 subjects (89.5%) had to discontinue using both tazarotene concentrations due to intolerance. Patch discontinuations for the remaining test materials were as follows: 7 subjects discontinued use of tretinoin microsphere gel 0.1%, 3 discontinued tretinoin cream 0.025%, 1 discontinued tretinoin gel 0.025%, and 1 discontinued adapalene gel 0.1%. None of the subjects discontinued use of the white petrolatum or the adapalene solution 0.1%. Adapalene gel and solution 0.1% were statistically (P<.01) less irritating than both tazarotene gels 0.1% and 0.05%, tretinoin microsphere gel 0.1%, and tretinoin gel 0.025%, and they were not statistically different from tretinoin gel 0.025%.

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