Purpose: To determine if there is a difference in the efficacy of refrigerated (previously reconstituted) versus freshly reconstituted botulinum toxin (Botox Cosmetic, Allergan, Irvine, CA, U.S.A.) in the treatment of lateral periorbital rhytids.
Methods: This is a randomized, double-blind, controlled, prospective study. Participants included individuals who were interested in the treatment of their lateral periorbital rhytids (crow's feet) and responded to signs posted in ophthalmology clinics at our institution. Patients were randomized to receive fresh botulinum toxin on 1 side and refrigerated (reconstituted 2 weeks prior) botulinum toxin on the other. Photographs were taken at the pretreatment visit and at the 2-week, 6-week, and 3-month post-treatment visits. Patients were asked to describe any improvement in the appearance of the rhytids at the 2-week visit, the appearance of the rhytids at the 6-week visit, the appearance of the rhytids at the 3-month visit, and finally, the duration of effect at the 3-month visit as well as whether any intervening loss of efficacy had been noted subjectively. The subjective information was recorded by 1 investigator (JIH) at each of the follow-up visits. At the conclusion of the study, the photographs were shown to an ophthalmic plastic and reconstructive surgery fellow, who did not participate in the interventional portion of the study, to determine the response to treatment. This physician was masked to the study protocol and purpose and looked at each photograph without knowledge of treatment arm or timeline. The physician used the Wrinkle Assessment Scale developed by Lemperle et al. to grade the lateral periorbital rhytids on a 0 to 5 scale.
Results: Forty-five patients were included in the final analysis. One patient felt there was a difference in the time of onset with the refrigerated toxin taking effect on day 3 versus day 4 for the fresh toxin. Unmasking revealed the following: 5 patients felt there was a greater effect on the freshly reconstituted side while 6 patients felt there was a greater effect on the refrigerated side. The independent physician evaluator determined there was a difference in effect between sides in 4 patients with the greater effect on the fresh side in 2 patients and the refrigerated side in 2 patients.
Conclusions: This study demonstrates that 2 weeks of refrigeration does not appear to significantly affect the time of onset or efficacy of botulinum toxin in the treatment of lateral periorbital rhytids.