These agents are another mainstay of acne treatment. Topical antibiotics commonly are used in conjunction with retinoids or benzoyl peroxide in patients with any degree of inflammatory acne. The most frequently used topical antibiotics are clindamycin and erythromycin. These drugs normally are applied once or twice daily. Benzoyl Peroxide and Benzoyl Peroxide Combinations. Benzoyl peroxide is inexpensive and available over the counter. It has a stronger effect on papules than tretinoin, but a weaker effect on comedones.Combinations of topical antibiotics and benzoyl peroxide increase efficacy and reduce antibiotic resistance in patients with P. acnes colonization. The preparations are available in gel form, and include 1 percent clindamycin with 5 percent benzoyl peroxide (BenzaClin) and 3 percent erythromycin with 5 percent benzoyl peroxide (Benzamycin). The preparations are equally effective in the treatment of acne. One study comparing combined 1 percent clindamycin and 5 percent benzoyl peroxide with 1 percent clindamycin alone found the combination product to be more efficacious, with less P. acnes resistance.This agent is a dicarboxylic acid that has bacteriostatic and keratolytic properties. Azelaic acid (Azelex) may be particularly effective in the treatment of acne with postinflammatory hyperpigmentation. Over-the-counter products may be used as primary or adjunctive treatments. Additional prescription topical agents include sulfacetamide (Klaron) and 10 percent sulfacetamide with 5 percent sulfur (Sulfacet-R). Sulfacetamide products are available in cream, gel, and wash formulations. These products generally are not
considered first-line therapies, but they may be used in patients who cannot tolerate other topical agents.