Combined use of botulinum toxin type A and B for forehead rhytides: a randomized, double-blind, split-face study.

Background: This is the first well-controlled study of the combined use of botulinum toxin type A (BoNT-A) and botulinum toxin type B (BoNT-B) for hyperkinetic lines in forehead. Objective: To evaluate the effectiveness and safety of a mixture of BoNT-A and BoNT-B with that of equipotent BoNT-A alone for treating patients with forehead rhytides. Materials and methods: Fourteen patients with forehead wrinkles completed this clinical study. On day 0, patients received a mixture of BoNT-A (5 U) and B (500 U) on one side of the forehead and BoNT-A (10 U) symmetrically on the other side. Clinical evaluation was made at the beginning and at weeks 1, 2, 4, 8, 12, and 16. Therapeutic efficacy was evaluated using clinical improvement scale by investigators and the subjective wrinkle assessment by patients. Results: According to investigator assessment, the differences between the average improvement scores of the two differently treated sides were not statistically significant at all follow-up visits. Moreover, the plateau of the clinical benefit was achieved at week 4. Conclusion: We observed the equivalent efficacy in the mixture of both toxins and BoNT-A alone. [ABSTRACT FROM AUTHOR]