Comparative Efficacy of Topical N-Acetylcysteine-Doxycycline versus Benzoyl Peroxide-Doxycycline in Moderate Acne Vulgaris: An Add-on Double-Blind Randomized Controlled Trial.

INTRODUCTION

Acne vulgaris is a prevalent skin disorder, especially among adolescents. While topical retinoid and benzoyl peroxide (BPO) are standard treatments, their side effects often decrease patient adherence.

OBJECTIVES

This study aimed to explore the efficacy and safety of topical N-acetylcysteine (NAC) plus doxycycline compared to BPO-doxycycline in moderate acne vulgaris.

METHOD: In this double-blind randomized clinical trial, 40 patients were allocated into one of two groups: Group A received 100 mg/day doxycycline+5% NAC, while Group B received 100 mg/day doxycycline +5% BPO. Patients were assessed over three months using total lesion count (TLC), Investigator Global Assessment (IGA), Global Acne Grading System (GAGS), and Cardiff Acne Disability Index (CADI). Statistical analysis was performed using STATA 14.2, with P<0.05 considered significant.

RESULTS

In comparison with BPO, NAC treatment led to a significantly greater improvement in CADI scores (MD=-3.60, 95% CI: -4.26 - -2.95, P<0.001), GAGS scores (MD = -9.76, 95% CI: -11.84 - -7.68, P<0.001), TLC (MD = -4.29, 95% CI: -6.38 - -2.19, P=0.002), inflammatory lesion count (MD = -2.93, 95% CI: -5.18 - -0.68, P=0.003), and IGA scores (MD = -0.85, 95% CI: -1.12 - -0.58, P<0.001). Repeated mixed measures ANOVA further confirmed significant between-group differences in GAGS scores at the second and third months of patients' follow-up. Only one patient reported mild scaling with receiving NAC.

CONCLUSION

Topical NAC combined with doxycycline was significantly more effective than BPO-doxycycline in acne treatment, with minimal adverse effects. These results indicate that NAC may serve as an acceptable alternative for the treatment of moderate acne vulgaris.