Background: Combination treatments for acne vulgaris, such as Benzamycin® (3% erythromycin/5% benzoyl peroxide) and Stievamycin® (0.025% tretinoin/erythromycin 4%), reduce bacterial growth, which contributes to the inflammatory lesions typical of adolescent acne, and also decrease the epidermal cell compaction which may form the characteristic noninflammatory comedone. Both agents contain erythromycin to reduce the growth of Propionibacterium acnes in skin. Benzoyl peroxide has antibiotic activity as well as anticomedogenic properties. Tretinoin may increase the turnover of epidermal cells and loosen the cells compacted to form comedones. A combination preparation containing the two antibiotics may reduce the development of resistance; the combination preparation containing tretinoin and erythromycin will have an antibiotic effect as well as acting on differentiation. Patients and Methods: This multicenter, randomized, double-blind, parallel group study compared the effectiveness of 3% erythromycin/5% benzoyl peroxide and 0.025% tretinoin/erythromycin 4%, each applied twice daily in patients with moderate acne vulgaris. Overall physician and patient ratings of severity of acne symptoms were performed at baseline and at weeks 2, 4, 8, and 12. Results: At baseline the two treatment groups had similar disease severity. The number of papules, pustules, and comedones was reduced in both treatment groups at week 12, and the reductions were not significantly different between the two comparators. Global physician rating of improvement was significantly higher in the 3 % erythromycin/5% benzoyl peroxide group compared with the 0.025% tretinoin/ erythromycin 4% group; however, there was no significant difference in global patient ratings between the two treatment groups. An aggregate score was produced, for both physician rating and patient rating, by adding up individual symptom severity ratings. Compared with 0.025% tretinoin/erythromycin 4%, 3% erythromycin/5% benzoyl peroxide provided significantly greater reduction in both physician- and patient-rated severity of acne symptoms; there was a significant difference between the two groups as early as week 2. The 3% erythromycin/5% benzoyl peroxide demonstrated significantly greater reduction of erythema and scaling, as evaluated by the study physician, compared with tretinoin 0.025%/erythromycin 4%. Patients judged 3% erythromycin/ 5% benzoyl peroxide to have a significantly greater effect on redness, dryness, oiliness, and burning. Conclusion: In moderate acne vulgaris, 3% erythromycin/5% benzoyl peroxide may provide a greater beneficial effect than 0.025% tretinoin/erythromycin 4%.
