Oxybutynin and its new transdermal application for the treatment of overactive bladder

It has long been accepted that antimuscarinic agents are the backbone of the pharmacological treatment of overactive bladder. Oxybutynin has been the gold standard of these medications for years due to its efficacy, but suffers from a lack of selectivity for the bladder, and extensive metabolism and lipophilicity result in significant side-effect issues. The transdermal delivery of oxybutynin turns this disadvantage of lipophilicity into an advantage. This, in turn, bypasses gastrointestinal absorption and metabolism by the cytochrome P450 system and reduces the breakdown into metabolites responsible for many of the side effects, while providing equivalent efficacy to the immediate-release oral formulation.