Reconstituted and frozen botulinum toxin A is as effective and safe as fresh for treating axillary hyperhidrosis: A retrospective study

The use of reconstituted and frozen left-over botulinum toxin A, for treatment of patients with axillary hyperhidrosis seems to be common practice in healthcare. Thus, the objective of this study was to investigate the efficacy and safety of frozen and thawed versus fresh reconstituted abobotulinum toxin (Dysport(®)) and onabotulinum toxin (Botox(®)) in the treatment of axillary hyperhidrosis. A retrospective study was conducted analysing efficacy and data from pre- and 24 weeks post-treatment questionnaires together with medical records of individuals with moderate to severe axillary hyperhidrosis. The patients had received fresh prepared botulinum toxin A in their right axilla while frozen and thawed botulinum toxin A had been administered in their left axilla. Treatment was conducted at our Hyperhidrosis Clinic, Umeå University Hospital, Sweden 2019–2021. Pre- and post-treatment questionnaires from 106 patients were analysed. The patients were 18 to 55 years old, with a mean age of 30.7 ± 9.9 years. No significant differences in patient-reported variables, Hyperhidrosis Disease Severity Scale and VAS 10-point scale, were found between the different preparations (frozen compared to fresh) for abobotulinum toxin and onabotulinum toxin, before treatment and at 6 months follow-up. Multivariable regression analysis resulted in no significant difference regarding side-effects between the preparations or brands of botulinum toxin. The findings of this study support our clinical experience that both abobotulinum toxin and onabotulinum toxin, reconstituted, frozen and thawed, seem to be as effective and safe as fresh prepared botulinum toxin when treating axillary hyperhidrosis. Our findings indicate that left-over preparations of abo- and onabotulinum toxins, stored and frozen for up to 6 months, is a cost-and time-effective way of handling botulinum toxin for treatment of axillary hyperhidrosis.