Brimonidine is an alpha-2 agonist. When applied to the face, it reduces erythema by causing cutaneous vasoconstriction.1
The efficacy of brimonidine gel in the treatment of facial erythema due to rosacea was evaluated in two randomised, controlled double-blind trials of identical design.2
In both studies, adults with moderate to severe erythema of rosacea were randomised 1:1 to apply topical brimonidine gel 3mg/g or vehicle gel once daily for four weeks, followed by a four-week follow-up phase.
The primary efficacy endpoint was 'success', defined as a two-grade improvement in both the Clinician's Erythema Assessment (CEA) and the Patient's Self-Assessment (PSA) on days one, 15 and 29.2
The pooled intention-to-treat population comprised 553 patients, of whom 277 were treated with brimonidine gel and 276 received vehicle gel.
Analysis showed that brimonidine gel was significantly more efficacious than vehicle gel in relieving erythema in both studies, with greater success rates observed at three, six, nine and 12 hours after gel application on days one, 15, and 29 (all p<0.001). On day 29, the success rate at 12 hours in the brimonidine gel groups was 22.8% in the first study and 21.1% in the second study, compared with 8.6% and 9.9%, respectively, in the vehicle gel groups.2
Onset of action was also evaluated. The secondary efficacy endpoint, a one-grade improvement in CEA and PSA at 30 minutes after gel application on day one, occurred in 27.9% and 28.4% of patients in the brimonidine gel groups, compared with 6.9% and 4.8% of patients in the vehicle gel groups (both p<0.001).2
A long-term open-label study (n=449) showed that the efficacy of brimonidine gel was maintained with daily use for up to one year. A total of 279 participants completed one year of treatment. The incidence of side-effects declined over the course of the study (from 49.1% in the first quarter to 19.5% in the fourth quarter) and was comparable between patients who were taking concomitant therapies for inflammatory lesions of rosacea and those who were not.3
The most commonly reported side-effects of topical brimonidine are erythema, pruritus, flushing and skin burning sensation, which are typically mild to moderate in severity and do not usually require discontinuation of treatment.1
1. Mirvaso Summary of Product Characteristics, February 2014.
2. Fowler J et al. J Drugs Dermatol 2013; 12: 650-6.
3. Moore A et al. J Drugs Dermatol 2014; 13: 56-61.