Efficacy and tolerability of low-dose spironolactone and topical benzoyl peroxide in adult female acne: A randomized, double-blind, placebo-controlled trial

Effective therapies for adult female acne (AFA) are limited. Oral spironolactone (SPL), 100-200 mg/day, is currently used off-label to treat AFA. However, high-dose SPL results in clinically significant side-effects which prevent widespread use in clinical practice. The efficacy of low-dose spironolactone in AFA is unknown. We examined the efficacy and tolerability of low-dose (25-50 mg/day) oral SPL in Thai women with moderate AFA. A randomized, double-blind, placebo-controlled trial was conducted for 12 weeks. Moderate AFA patients aged between 25 and 45 years received a combination of daily topical benzoyl peroxide (BP) 2.5% plus either SPL 25 mg (SPL25 group), SPL 50 mg (SPL50 group) or placebo. We performed total acne counts and Adult Female Acne Scoring Tool (AFAST) grading at 4-week intervals. The success rate, defined as the proportion of participants achieving a "clear/almost clear" AFAST grade by the end of week 12, was considered as the main outcome. Treatment-related adverse events (TRAE) were recorded. We enrolled 63 participants in the study. The total acne counts decreased significantly in all three groups (P < 0.05) as compared with baseline. Participants in the SPL50 group had a significantly higher success rate than those in the placebo group (P < 0.05). Serum potassium and creatinine levels showed no significant changes with treatment or between groups. A small number of participants in SPL25 and SPL50 reported mild and temporary TRAE, such as menstrual irregularities, breast tenderness and dizziness. The combination of SPL 50 mg/day and topical BP proved effective in improving moderate AFA in Thai women, with an acceptable side-effect profile. We propose this regimen as an option for treating moderate AFA.