Objective: To investigate the efficacy and safety of 2 injection site patterns (3- and 5-injection patterns [30 and 50 U]) of botulinum toxin A (Dysport; Ipsen Pharma, Ettlingen, Germany), in the treatment of glabellar and central forehead wrinkles.
Design: Multicenter, double-blind, placebo-controlled, randomized, 16-week trial.
Setting: Twenty-three German dermatologic centers.
Patients: Two hundred twenty-one patients with moderate or severe glabellar wrinkles when frowning maximally. Intervention Centers were randomly assigned to the 3-injection site pattern (3 injections of 10 U of botulinum toxin A or placebo) or 5-injection site pattern (5 injections of 10 U of botulinum toxin A or placebo). All centers used 3 sites in the procerus and corrugator muscles; the 2 additional sites were approximately 1-cm cranial from the corrugator sites.
Main outcome measure: Wrinkle severity was graded by 4 independent experts blinded to the treatment received using digital photographs and a standardized clinical scale (range, 0 [no wrinkles] to 3 [severe wrinkles]). A reduction of at least 1 point between weeks 0 and 4 was considered a therapeutic success (responder).
Result: One hundred ten patients (73 receiving botulinum toxin A vs 37 receiving placebo) received 3 injections; 111 patients (73 receiving botulinum toxin A vs 38 receiving placebo) received 5 injections. After 4 weeks, the proportions of responders were 86.1% vs 18.9% and 86.3% vs 7.9%, respectively (P<.001 for both). No major adverse effects were observed.
Conclusions: The 3 central injection sites are essential for the treatment of glabellar wrinkles. The 2 additional injection sites in the forehead region, targeting the frontalis muscle, did not significantly improve efficacy.