Effect of oxybutynin on exercise-induced sweating in healthy individuals

Objectives: Oxybutynin has been proven to be effective in patients with generalized hyperhidrosis. Some dermatoses aggravate as a result of sweating. Therefore, oxybutynin might also be useful in such normohidrotic patients. The aim was to evaluate the efficacy and safety of different doses of oxybutynin on exercise-induced sweating in healthy individuals. Methods: Two randomized, double-blind, placebo-controlled, cross-over studies were performed, in which two different dosages (2.5 and 5 mg) of oxybutynin were tested. The degree of sweating was determined by transepidermal water loss (TEWL) measurement on the forearm and the hand during exercise. Furthermore, the effectiveness was evaluated by means of the individual's global assessment score, and side effects were noted. Results: No significant differences between oxybutynin and placebo were found on the forearm and the hand at both dosages of oxybutynin with respect to TEWL values and the individual's global assessment score. Side effects consisted of diarrhoea, dizziness, dry mouth and dry eyes. Conclusions: In this model, oxybutynin did not result in inhibition of exercise-induced sweating in healthy volunteers.