June 22, 2011
A Better Botox?
(Ivanhoe Newswire) "“ Not all varieties of botulinum toxin seem to be equally effective in reducing crow's feet wrinkles, according to a new report.
Botulinum toxin type A was approved in the United States in 1989 for two muscular conditions that affect the appearance of the eyes. In 2002, one type"”onabotulinumtoxinA"”was approved for the treatment of wrinkles between the eyebrows; and a second type, abobotulinumtoxinA, was approved for the same use in 2009.
Kartik D. Nettar, M.D., from The Maas Clinic, San Francisco, and the University of California, San Francisco, and colleagues wanted to compare both types of the protein, head to head. "Such an assessment could characterize and contrast their efficacy in clinical performance in the treatment of hyperfunctional lines and muscular relaxation," the authors write.
The researchers preformed a double-blind split-face study, using one agent on the right side of the face and the other agent on the left side. "By using a split-face paradigm, this would provide direct comparison of each product in the same patient," the authors write.
Ninety patients received injections of onabotulinumtoxinA and of abobotulinumtoxinA on either side of their faces. The "crow's feet" wrinkles, technically know as lateral orbital rhytids, were the part of the face treated.
The team believes the difference between the two agents was noticeable when participants tightened the muscles as much as possible, with abobotulinumtoxinA producing a greater effect. Two-thirds of participants said they favored the side of their faces that was treated with abobotulinumtoxinA.
The researchers plan to do more comparative studies in other facial muscles, and to study in detail why one agent would perform better than the other. "Ongoing studies will determine whether the demonstrated patient preference and early advantage in clinical outcomes is persistent," the authors write.
SOURCE: Archives of Facial Plastic Surgery, of the JAMA/Archives journals, June 21, 2011.