WEDNESDAY, June 7, 2023 (HealthDay News) -- Spironolactone improves acne compared with placebo, with greater differences seen at week 24 than week 12, according to a study published online May 17 in The BMJ.

Miriam Santer, M.B., B.Chir., from the University of Southampton in the United Kingdom, and colleagues conducted a multicenter, phase 3 trial to examine the effectiveness of oral spironolactone for acne vulgaris in adult women with facial acne for at least six months, judged to warrant oral antibiotics. Participants were randomly assigned to 50 mg/day spironolactone or matched placebo until week 6, increasing to 100 mg/day spironolactone or placebo until week 24. The primary analysis included 342 women (176 in the spironolactone group and 166 in the placebo group).

The researchers found that at baseline and week 12, respectively, the mean acne quality-of-life symptom scores were 13.2 and 19.2 for the spironolactone group and 12.9 and 17.8 for the control group (difference, 1.27 favoring spironolactone). At week 24, scores were 21.2 and 17.4 for spironolactone and placebo, respectively (difference, 3.45). More participants in the spironolactone versus placebo group reported acne improvement, with a significant difference seen at week 24 (82 versus 63 percent; odds ratio, 2.72). Treatment success was 19 and 6 percent for spironolactone and placebo, respectively, at week 12 (odds ratio, 5.18). The spironolactone group had adverse reactions slightly more often (20 versus 12 percent).

"Adopting a combined approach using oral spironolactone and topical agents has the potential to reduce the long-term prescribing of oral antibiotics and therefore to reduce the likelihood of emerging bacterial resistance," the authors write.

One author disclosed ties to the pharmaceutical industry.