Effects of the abobotulinumtoxinA with different dilution on the treatment of the upper face.

The effectiveness of AbobotulinumtoxinA (BoNT-ABO) depends on numerous factors, including the amount of dose, presence of autoantibody and number of injected muscles. In this study, we aimed to investigate the effect of the BoNT-ABO in different dilutions, age groups, and the number of sessions. A total of 60 patients with upper facial wrinkles were included in the study. A 500-unit vial of BoNT-ABO was reconstituted with 2.5 mL preservative-free normal saline for 30 patients and 4 mL saline for the other 30 patients for injection. There was no statistically significant difference between 2.5 mL (4.80 ± 2.08 months) and 4 mL (4.20 ± 1.72 months) group in terms of duration effect of BoNT-ABO (P = 0.228). There were no significant differences mean duration of effect between the age at ≤40 and > 40 years for each dilutions containing 2.5 and 4 mL. (P = .856, P = .966, respectively). There was no correlation between the number of sessions and the duration of the effect (P = 0.229, C = -0.158). In conclusion, although the difference was not statistically significant, the 2.5 mL dilution of the BoNT-ABO seems to have a longer effect than 4.0 mL dilution. The low number of sessions of BoNT-ABO and patients with ≤40 years of age do not have a remarkable longer duration of the effect of BoNT-ABO.