[Therapeutic value of moderate-dose oxybutynin in extensive hyperhidrosis]

Background: Hyperhidrosis is a functional disorder characterized by increased sweating that can greatly impair quality of life due to psychosocial factors. It is most often localized (underarms, hands, feet) but can also be generalized. In this case, after eliminating an underlying cause, systemic treatment may be proposed. In this retrospective study, we report the benefits and adverse effects of the anticholinergic drug oxybutynin.

Patients and methods: All patients treated with oxybutynin between February 2008 and October 2010 for troublesome generalized hyperhidrosis were recruited after ruling out underlying disease. Oxybutynin (Ditropan(®)) was started at a dose of 1.25mg then increased in increments of 1.25mg every 4 days up to the lowest effective dose, which did not exceed 2.5mg three times per day in order to avoid serious adverse effects. After 2 months of treatment, patients were asked to rate their satisfaction on a scale of 0 to 10, as well as degree of efficacy, time to efficacy, type of adverse effects and whether or not treatment was continued.

Results: Thirty patients were included in this study: 24 women and 6 men aged 19 to 64 years (mean=33 years). The treatment was rated by 24 patients (80%) as very effective and by three patients (10%) as moderately effective. Three patients (10%) stopped the treatment due to adverse effects such as faintness and ocular accommodation disorders, and for these patients, the degree of satisfaction ranged from 1 to 3/10. For the other 27 patients, satisfaction was 6 to 10 with a median of 8.5. The onset of action was between 10 and 21 days with an average of 15.4 days. Adverse effects were present in 10 of 27 patients (37%) comprising dry mouth, which was well tolerated (grade 1). Mean follow-up was 14.9 months (2 months to 32 months), with two patients being lost to follow-up.

Discussion: The treatment of primary extended or generalized hyperhidrosis is not currently codified. Our study shows the efficacy of oxybutynin in this indication at a moderate dose, with good safety. The satisfaction index was high, with 80% of patients considering the drug very effective and for 10% considering it moderately effective. To our knowledge, this is the first retrospective study in a large population. A placebo-controlled study could provide the grounds for a therapeutic consensus concerning a drug widely known for many years in the treatment of extensive hyperhidrosis.