Two percent metronidazole gel was an effective, safe and well-tolerated topical medication in the treatment of moderate facial acne vulgaris in a recent study.
Seventy adults (44 women), aged 18 to 30 years, with acne vulgaris participated in the double blind, placebo-controlled, split-face clinical trial from September 2010 through July 2011 in Tabriz, Iran. The patients’ mean duration with acne was 3.03 years.
Patients were divided into two groups based on skin type: normal/dry (non-oily) skin and oily skin. On the right side of each patient’s face, topical 2% metronidazole gel was applied twice daily for 8 weeks, while a water-based neutral gel placebo that was similar in appearance and packaged in the same type of tube was applied to the left side. All patients completed the study, with follow-up at day 2 and weeks 1, 2, 4 and 8. A dermatologist assessed and documented counts of inflamed and noninflamed lesions, presence of erythema, facial skin type and any complications or side effects.
On baseline examination, both sides of the patients’ faces were comparable. At follow-ups, the mean lesion counts decreased on the right side (repeated-measures analysis, P<.001). At the 8-week endpoint, the number of cases with erythema and oily skin on the metronidazole-treated right side had decreased by 85.7% and 87.1%, respectively (P<.001 for both). There was no change to the left side of the patients’ faces. Satisfaction was reported by 88% of the patients regarding right-side treatment results. Side effects of the metronidazole were mild burning sensation and mild skin dryness in 22 and 16 patients, respectively.
“The high efficacy of 2% metronidazole gel [comes] despite the fact that Propionibacterium acnes have traditionally been considered a metronidazole-resistant microorganism,” the researchers said. “So, mechanisms other than microbicidal action may underlie the therapeutic effect of metronidazole, such as anti-inflammatory, immunosuppresive and anti-itching actions, as well as the inhibition of free radical generation by human neutrophils.”