Botulinum toxin type a is a safe and effective treatment for axillary hyperhidrosis over 16 months: a prospective study.

OBJECTIVE To evaluate the safety and efficacy of botulinum toxin type A (BTX-A) (BOTOX) over 16 months in the treatment of bilateral primary axillary hyperhidrosis. DESIGN A 16-month study with initial double-blind randomization to 50 U of BTX-A or placebo per axilla. After 4 months, participants could receive up to 3 further treatments with open-label BTX-A over 12 months. SETTING Fourteen dermatology or neurology clinics in Germany, Belgium, and the United Kingdom. PARTICIPANTS Of 207 individuals aged between 17 and 74 years who had persistent bilateral primary axillary hyperhidrosis that interfered with daily activities, 174 (84%) completed the study. The baseline gravimetric assessment was a spontaneous sweat production of 50 mg or greater in each axilla prior to initial treatment. MAIN OUTCOME MEASURES At week 4 after each treatment, the response rate of subjects who had at least a 50% reduction from baseline in axillary sweating, as measured by gravimetric assessment, was evaluated. Adverse events were spontaneously reported throughout the study, together with quality-of-life parameters and assessment of neutralizing antibodies to BTX-A. RESULTS Over the 16-month period, 356 BTX-A treatments were given to 207 subjects. After placebo treatment, the response rate at week 4 was 34.7%. After the first, second, and third treatment with BTX-A, response rates at week 4 were 96.1%, 91.1%, and 83.3%, respectively. For subjects receiving more than 1 treatment, the mean duration between BTX-A treatments was approximately 7 months; however, 28% of subjects completed the study after only 1 BTX-A treatment. Subjects' satisfaction after treatments was consistently high, their quality of life improved, and there was a reduction in the impact of the disease on their lives. The safety profile of BTX-A after repeated treatments was excellent and no confirmed positive results for neutralizing antibodies to BTX-A occurred. CONCLUSION Repeated intradermal injections of BTX-A over 16 months for treatment of primary axillary hyperhidrosis is safe and efficacious.