Cumulative Irritation Potential Among Metronidazole Gel 1%, Metronidazole Gel 0.75%, and Azelaic Acid Gel 15%

Topical therapy for rosacea aims to reduce inflammatory lesions and decrease erythema but can carry side effects such as stinging, pruritus, and burning. Metronidazole and azelaic acid gel 15% are US Food and Drug Administration–approved for the treatment of rosacea. The current study was conducted to assess the cumulative irritation potential of 2 formulations of metronidazole—0.75% gel and 1% gel—and azelaic acid gel 15% over 21 days (N=36). Results of this study demonstrated a significantly greater potential for irritation from azelaic acid compared with metronidazole gel 0.75% (P