Low-dose efficacy of botulinum toxin A for axillary hyperhidrosis: a randomized, side-by-side, open-label study.

Objective: To compare 2 doses of botulinum toxin A in view of dose-dependent efficacy, longevity, and safety.

Design: Side-by-side, controlled, randomized clinical trial with extended follow-up over 2 treatment cycles. Patients were injected with 200 U of botulinum toxin A (Dysport; Ipsen Ltd, Wrexham, England) into one axilla and 100 U into the other axilla in a randomized fashion. After 48 weeks of follow-up, the patients were given a second treatment with identical doses to the respective axillae and were again followed up for 48 weeks. Gravimetric measurements of sweat production and the patients' own rating of sweating were monitored.

Setting: University-based outpatient clinic.

Patients: Forty-three subjects with primary axillary hyperhidrosis that was unresponsive to topical therapy.

Main Outcome Measure: Absolute values of sweat production.

Results: Two weeks after treatment, the sweat production was significantly reduced compared with baseline levels. Both doses were equally effective. At week 48, the sweat production had returned to baseline levels irrespective of the dose. After the second treatment, both doses were again equally effective at any follow-up point. At the end of the follow-up period (96 weeks) for the second treatment, the sweat production was significantly lower than at the end of the first follow-up period (48 weeks). The treatment was well tolerated, and there were no lasting or severe adverse effects.

Conclusions: Short- and long-term results show that doses of 100 and 200 U of botulinum toxin A are equally safe and effective. However, because of cost considerations and possible adverse effects, the lower dose is preferable for treating axillary hyperhidrosis.