Results of a new study indicate that Botox (onabotulinumtoxinA, Allergan) can be used to treat crow’s feet lines safely and effectively.
The two-phase three clinical trials, carried out by Carruthers et al, analysed 1,362 patients with crow’s feet lines who were treated with either a 24U dose of onabotulinumtoxinA or a placebo.
The researchers used two different injection patterns that included three injections of onabotulinumtoxinA per side, depending on the crow’s feet line pattern.
Crow’s feet lines were graded by the researchers according to their severity and efficacy of treatment using the Facial Wrinkle Scale and a photonumeric guide.
At 30 days, patients who received onabotulinumtoxinA had a significantly higher responder rate compared with patients who received placebo (P < 0.001).
The crow’s feet lines were classified into four different patterns: full fan, lower fan, central fan, and upper fan. Overall, full fan, central fan and lower fan crow’s feet lines comprised 90% of cases, and upper fan comprised 10% of cases. The only adverse event recorded was eyelid edema, which was reported in 1% of patients who received onabotulinumtoxinA.