Study suggests extra botulinum toxin A injections may be unnecessary in treating glabellar wrinkles

Berlin -- According to a study reported in the March issue of the Archives of Dermatology, while three central injection sites are essential for the treatment of glabellar wrinkles with botulinum toxin A, the use of two additional injection sites targeting the frontalis muscle did not improve efficacy.

Researchers from the Klinik für Dermatologie and Charité Universitätsmedizin in Berlin, and colleagues from the GLADYS Study Group conducted a double-blind study of 221 patients. Of these patients, one group of 110 received three injections, including 73 receiving botulinum toxin A and 37 receiving placebo; the second group of 111 patients received five injections, including 73 receiving botulinum toxin A and 38 receiving placebo. After four weeks, patients’ level of satisfaction was generally good, but 29.4 percent in the three-injection group reported moderate satisfaction, while 23.3 percent in the five-injection group reported moderate satisfaction. No major adverse effects were reported.

The study concluded that the three central injection sites are essential for the treatment of glabellar wrinkles, but that the two additional injection sites in the forehead region, targeting the frontalis muscle, did not significantly improve efficacy.

The study authors noted limitations, include inability to rule out the possibility that evaluation of central forehead wrinkles would have shown the five-injection site pattern to be more effective; debate over the best outcome criteria; and difficulty with blinding.