Topical oxybutynin deodorant for axillary hyperhidrosis: a topic or a systemic effect? Rationale and design of the phase II today trial.

Anticholinergics have been shown to enhance quality of life and reduce sweat in patients with hyperhidrosis. However, it remains unclear whether topical application specifically exerts local or systemic effects. This study's primary aim is to assess topical oxybutynin's impact on axillary hyperhidrosis. Twenty patients will be randomized into three groups. Group A will receive 2.5 mg of oral oxybutynin from day 1 to day 35 (on a variable frequency regimen). Group B will be administered a topical placebo for 35 days and Group C will receive a 10% oxybutynin topical spray, to be used twice daily for 35 days. The primary efficacy outcome will be the evaluation of the effectiveness of topical oxybutynin spray in treating hyperhidrosis. The TODAY trial will generate high-quality evidence on the effects of topical oxybutynin, assessing whether its impact is local or systemic in patients with axillary hyperhidrosis.