You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.

A Lower Dose of Botulinum Toxin A May Be Indicated for Axillary Hyperhidrosis

Authors: News Author: Laurie Barclay, MD CME Author: Penny Murata, MDFaculty and Disclosures


Oct. 21, 2005 -- For axillary hyperhidrosis, a lower dose of botulinum toxin A may be indicated, according to the results of a randomized study reported in the October issue of the Archives of Dermatology.

"Botulinum toxin A blocks the autonomic innervation of sweat glands and has therefore become a preferred treatment modality for severe axillary hyperhidrosis that is unresponsive to other established therapies, eg, topical application of aluminum chloride," write Marc Heckmann, MD; from the Skin Care Centre and Clinic in Starnberg, Germany, and Gerd Plewig, MD, from the University of Munich in Munich, Germany, for the Hyperhidrosis Study Group. "The issue of finding the optimal dose is complicated by the fact that there are two distinct pharmaceutical preparations of botulinum toxin A: Botox (Allergan, Irvine, Calif[ornia]) and Dysport (Ipsen Ltd, Wrexham, England). Both products are measured in mouse units, but the respective units appear to have different clinical potencies in humans."

In this side-by-side trial at a university-based outpatient clinic, 43 patients with primary axillary hyperhidrosis that was unresponsive to topical therapy received injections with 200 U of botulinum toxin A (Dysport) into one axilla and 100 U into the other axilla in a randomized fashion. After 48 weeks of follow-up, the patients received a second treatment with identical doses to the respective axillae and were again followed up for 48 weeks with gravimetric measurements of sweat production and patient ratings of sweating.

Compared with baseline levels, sweat production was significantly reduced two weeks after treatment, and both doses were equally effective. Regardless of dose, sweat production had returned to baseline levels at week 48, but after the second treatment, both doses were again equally effective at any follow-up point.

At 96 weeks, or the end of the follow-up period for the second treatment, sweat production was significantly lower than at the end of the first follow-up period (48 weeks). Treatment with both dosages was well-tolerated, with no lasting or severe adverse effects.

Study limitations include lack of placebo control or double blinding.

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

Ludwig-Maximilians Universität, Munich, and Ipsen-Pharma, Ettlingen, Germany, have disclosed that they supported this study. Dr. Heckmann has disclosed that he received research grants from Allergan, Irvine, California, and Ipsen Ltd, Wrexham, England, both the makers of botulinum toxin A, for other research projects.

Arch Dermatol. 2005;141:1255-1259