RimabotulinumtoxinB versus OnabotulinumtoxinA in the Treatment of Masseter Hypertrophy: A 24-Week Double-Blind Randomized Split-Face Study

Abstract

BACKGROUND: Masseter hypertrophy can be ameliorated by botulinum toxin. OBJECTIVE: To compare the efficacy and safety of RimabotulinumtoxinB (BTX-B) and OnabotulinumtoxinA (BTX-A) in the treatment of masseter hypertrophy. METHODS: Sixteen women with bilateral masseter hypertrophy received single injections of BTX-A or BTX-B at a dose ratio of 1:50 or 1:70 in a 24-week double-blind randomized split-face study. RESULTS: Both BTX-A and BTX-B produced significant improvements in masseter hypertrophy. The maximum volume reduction, as determined by computed tomography scanning, at week 12 was comparable between BTX-A and BTX-B at a dose ratio of 1:70 (15.6 and 14.2%, respectively). At week 24, only masseters treated with BTX-A maintained a significant volume reduction. Investigator ratings and patient satisfaction scores paralleled objective computed tomography measurements. CONCLUSION: Both BTX-A and BTX-B are effective in the treatment of masseter hypertrophy. BTX-B, at a dose ratio of 1:70, has a comparable efficacy but a shorter duration of action than BTX-A.