Evolution of transdermal oxybutynin in the treatment of overactive bladder

Overactive bladder (OAB) syndrome affects millions of people worldwide. In addition to adversely affecting quality of life, the direct and indirect costs in managing patients with OAB incur a substantial financial burden on health services. Among the approved anticholinergics for treating OAB, oxybutynin is the most extensively studied drug in clinical trials. The principle metabolite of oxybutynin has a higher affinity for muscarinic receptors in salivary glands which lead to significantly high dry mouth rates. This prompted the development of alternative formulations of oxybutynin aiming to achieve better tolerability whilst sustaining efficacy. This editorial examines the efficacy and tolerability of transdermal oxybutynin (OXY-TD) in treating OAB. Articles were retrieved from PubMed between 2000 to the present day relating to OXY-TD. Data is presented from phase I-IV trials. The results from placebo-controlled trials indicate that OXY-TD is efficacious in treating patients with OAB associated with urge urinary or mixed incontinence. Systemic side effects most notably dry mouth, appear to be less with this formulation compared with oral anticholinergics. However, further study is required in different OAB populations. The main limitation appears to be related to application site adverse events such as pruritus and erythema. OXY-TD is likely to find its place as first-line pharmacotherapy in the clinicians' armamentarium in treating OAB.