Overactive bladder (OAB), often accompanied by urinary incontinence, is most 
prevalent among the elderly, but also affects many middle-aged men and women in 
the US. OAB may severely impair quality of life, and its overall economic costs 
to society are substantial. Although antimuscarinic agents relieve OAB symptoms 
effectively, treatment persistence generally is low. This has been attributed in 
part to the occurrence of dry mouth and other anticholinergic adverse events. 
High plasma concentrations of N-desethyloxybutynin (DEO), an active metabolite 
of oxybutynin, have been identified as the major cause of anticholinergic 
adverse effects associated with oral oxybutynin. Transdermal formulations of 
oxybutynin generate much lower DEO plasma concentrations compared with oral 
formulations. In a placebo-controlled US Phase III study in patients with OAB, 
the recently approved oxybutynin topical gel (OTG) was efficacious and well 
tolerated. Dry mouth occurred in 6.9% of patients treated with OTG and 2.8% of 
patients on placebo. Incidences of other anticholinergic events were low and 
similar for OTG and placebo. OTG rarely caused application site skin reactions. 
OTG provides significant benefits to patients with OAB, particularly those who 
are sensitive to anticholinergic adverse effects.