Botulinum toxin type A in the treatment of bilateral primary axillary hyperhidrosis: Efficacy and duration with repeated treatments

BACKGROUND. Botulinum toxin type A (BTX-A) has been shown to be effective for the temporary reduction of local hyperhidrosis. OBJECTIVE. To investigate the duration of efficacy of BTX-A with repeat treatments for axillary hyperhidrosis. METHODS. Patients who completed a prior randomized, controlled, parallel-group study comparing BTX-A with vehicle for bilateral primary axillary hyperhidrosis were eligible for this 18-month, open-label, noncomparative, follow-up study. Patients had to request further treatment, fulfill the preceding study inclusion/exclusion criteria, and have spontaneous sweat production that was more than 50% of the baseline value of the previous study. Patients received up to four treatments of intradermal BTX-A (2 mL, 50 U). All of the 12 patients who were enrolled completed the study. Two of the 12 patients (17%) were previously treated with placebo. RESULTS. In the 18 months of study and follow-up, five patients (42%) required a total of two active injections. Three patients (25%) required a total of three active injections, and four patients (33%) required a total of four active injections. The response rate was 83% (10 of 12) at 4 weeks after the first treatment. The mean percentage change from baseline in overall sweat production was approximately 80% at Week 4. The mean time between the first and second treatment in this study was just over 29 weeks, with a range of 17.8 to 57.5 weeks. CONCLUSION. BTX-A is an effective repeat treatment for axillary hyperhidrosis giving variable but clinically helpful remission. No clinically relevant changes in vital signs or safety parameters were noted.